If $$f(x)= (x^{2} + 3x)(x^{2}+ 3x+2)$$ then the sum of all real roots of the equation $$\sqrt{f(x)+1}= 9701$$, is
CAT Functions, Graphs and Statistics Questions
Let $$(x^2+3x)$$ be equal to $$k$$. We have,
$$f(x)= k(k+2) = k^2+2k$$
Therefore, $$\sqrt{f(x)+1} = \sqrt{k^2+2k+1} = \sqrt{(k+1)^2} = k+1 = 9701$$
We get $$k=9700$$.
Thus, $$x^2+3x=9700$$ or $$x^2+3x-9700 = 0$$
Since $$x$$ is real, the discriminant of the above quadratic has to be greater than or equal to zero.
We find that $$3^2 + 4*9700 \geq 0$$ and therefore the quadratic has real roots.
The sum of the roots will be $$-\dfrac{b}{a} = -\dfrac{3}{1} = -3$$
Option D is the correct answer.
For real values of x, the range of the function $$f(x)=\dfrac{2x-3}{2x^{2}+4x-6}$$ is
Let $$y= \dfrac{2x-3}{2x^{2}+4x-6}$$
$$\Rightarrow 2yx^2 + 4yx - 6y = 2x - 3$$
$$\Rightarrow 2yx^2 + (4y-2)x - 6y + 3 = 0$$
Equation (1) is a quadratic in $$x$$, where $$x$$ is real. Therefore, the discriminant of the quadratic has to be greater than or equal to zero.
$$(4y-2)^2 + 4\times 2y\times (6y-3) \geq 0$$
$$16y^2 + 4 - 16y - 24y + 48y^2 \geq 0$$
$$64y^2 - 40y + 4 \geq 0$$
$$16y^2 - 10y + 1 \geq 0$$
The roots of the quadratic above will be $$\dfrac{10\pm 6}{32} = \dfrac{1}{2}$$ or $$\dfrac{1}{8}$$
Since the coefficient of $$y^2$$ is positive, the quadratic will be less than zero in the range $$\left(\dfrac{1}{8},\dfrac{1}{2}\right)$$
The quadratic will be greater than or equal to zero otherwise.
Therefore, the domain the quadratic, or possible values of $$y$$, which is the range of $$f(x)$$, will be,
$$\left(-\infty, \dfrac{1}{8}\right] \cup \left[\dfrac{1}{2}, \infty \right)$$
Option C is the correct answer.
Let $$f(x)=\frac{x}{(2x-1)}$$ and $$g(x)=\frac{x}{(x-1)}$$. Then the domain of the function $$h(x)=f(g(x))+g(f(x))$$ is all real numbers except
We check where $$f(x)=\frac{x}{2x-1}$$ or $$g(x)=\frac{x}{x-1}$$, or their compositions, become undefined.
First, f(x) is undefined at $$x=\tfrac12$$ and g(x) is undefined at $$x=1$$.
Next, for $$f(g(x)) = \frac{x}{x+1}$$
Since, the denominator can't be zero, x=-1 must also be excluded.
For $$g(f(x)) = \frac{x}{1-x}$$
$$\Rightarrow x=1$$ is not possible, which is already excluded.
So the values at which $$h(x)=f(g(x))+g(f(x))$$ is undefined are $${-1,\ \tfrac12,\ 1}$$
Consider two sets $$A = \left\{2, 3, 5, 7, 11, 13 \right\}$$ and $$B = \left\{1, 8, 27 \right\}$$. Let f be a function from A to B such that for every element in B, there is at least one element a in A such that $$f(a) = b$$. Then, the total number of such functions f is
Set A={2,3,5,7,11,13} so |A|=6
Set B={1, 8, 27} so |B|=3
Without any restrictions, each element in A can map to any of the 3 elements in B. Thus, the total number of functions is: $$3^6=729$$
Excluding Functions That Miss One Element in B: If a function does not map to an element in B, there are 2 elements in B left for mapping. The total number of such functions (for each specific element not mapped) is: $$2^6=64$$
Since there are 3 elements in B, the total number of such functions is:3x64=192
Adding Back Functions That Miss Two Elements in B:
If a function misses two elements in B, there is only 1 element left for mapping. The total number of such functions is: 1^6=1.
Since there are $$^3C_2$$ ways to choose which two elements are missed, the total number of such functions is: 3
Using the inclusion-exclusion principle, the number of functions where all elements of B are mapped by at least one element of A is:
729-192+3=540.
A function f maps the set of natural numbers to whole numbers, such that f(xy) = f(x)f(y) + f(x) + f(y) for all x, y and f(p) = 1 for every prime number p. Then, the value of f(160000) is
Looking at the additional information about the prime numbers should make one realise that they are the key to solving the question.
f(16000) can be written as $$f\left(2^8\times\ 5^4\right)$$
Now, we can try to find these individual values:
For any prime p: f(p)=1
$$f\left(p^2\right)=f\left(p\right)f\left(p\right)+f\left(p\right)+f\left(p\right)=1+1+1=3$$
$$f\left(p^3\right)=f\left(p^2\right)f\left(p\right)+f\left(p^2\right)+f\left(p\right)=3+3+1=7$$
This way, we can find the function output for any prime number raised to a power.
We can see that each new exponent is twice the previous output +1, solving this way till prime raised to power 8
$$f\left(p^4\right)=7+7+1=15$$
$$f\left(p^5\right)=15+15+1=31$$
$$f\left(p^6\right)=31+31+1=63$$
$$f\left(p^7\right)=63+63+1=127$$
$$f\left(p^8\right)=127+127+1=255$$
Using these values in the original expression of $$f\left(2^8\times\ 5^4\right)=f\left(2^8\right)f\left(5^4\right)+f\left(2^8\right)+f\left(5^4\right)$$ we get
$$f\left(2^8\times\ 5^4\right)=\left(255\times\ 15\right)+255+15=4095$$
Therefore, Option A is the correct answer.
The number of distinct real values of x, satisfying the equation $$max \left\{x, 2\right\} - min\left\{x, 2\right\} = \mid x + 2 \mid - \mid x - 2 \mid$$, is
The expression on the right-hand side will have two critical points: 2 and -2
For any value of x greater than equal to 2, the equation changes to x+2-(x-2) = 4
the value of min{x,2} would be 2, so we would want max{x,2} to be 4+2 = 6
Therefore, x=6 works.
For any value of x less than equal to -2, the equation changes to -(x+2)+(x-2) = -4
the value of max{x,2} would be 2, so we would want min{x,2} to be 6 again; this cannot be the case.
In general, subtracting the smaller (min) of the two values from the bigger (max) can not lead to a negative number. The max it can lead to is a 0
When x lies between -2 and 2, the equation becomes 2x
The maximum function will give back 2, and the minimum function will give back x, with the right-hand side giving 2x
Solving this we would get 2-x = 2x which is x=2/3
Therefore, there are two real values of x for which the given equation holds.
Hence, 2 is the correct answer.
The graph of the function on the right hand side can be visualised as:
Hence, 2 is the correct answer.
For any non-zero real number x, let $$f(x) + 2f \left(\cfrac{1}{x}\right) = 3x$$. Then, the sum of all possible values of x for which $$f(x) = 3$$, is
We are given, $$f(x) + 2f \left(\cfrac{1}{x}\right) = 3x$$
Substituting $$\frac{1}{x}\ for\ x$$
$$f\left(\dfrac{1}{x}\right)+2f\left(x\right)=\dfrac{3}{x}$$
Multiplying the second equation by 2 we will have
$$2f\left(\dfrac{1}{x}\right)+4f\left(x\right)=\dfrac{6}{x}$$
Subtracting the first equation from the second equation we have,
$$3f\left(x\right)=\frac{6}{x}-3x$$
$$f\left(x\right)=\frac{2}{x}-x$$
We want the sum of values when this function equals 3,
$$\frac{2}{x}-x=3$$
$$x^2+3x-2=0$$
Since the discriminant is greater than zero, both values of x will be real, and we can directly take the sum of values of $$x$$ to be,
$$-\frac{3}{1}$$
Answer is -3.
The area of the quadrilateral bounded by the Y-axis, the line x = 5, and the lines $$\mid x-y\mid-\mid x-5\mid=2$$, is
From the inequality and nature of x, and y, we get the given diagram:
We need to find the area of the quadrilateral ABDE = area of rectangle ABCD + area of triangle CDE
=> Area of ABCD = (7-3)*5 = 20 units, and the area of triangle CDE = (1/2)*10*5 = 25 units.
Hence, the area of the quadrilateral ABDE = (20+25) = 45 units.
Suppose f(x, y) is a real-valued function such that f(3x + 2y, 2x - 5y) = 19x, for all real numbers x and y. The value of x for which f(x, 2x) = 27, is
Given that f(3x + 2y, 2x - 5y) = 19x.
Let us assume the function f(a,b) is a linear combination of a and b.
=> f(3x+2y, 2x-5y) = m(3x+2y) + n(2x-5y) = 19x
=> 3m + 2n = 19 and 2m - 5n = 0
Solving we get m = 5 and n = 2
=> f(a,b) = 5a+2b
=> f(x,2x) = 5x + 2(2x) = 9x = 27 => x = 3.
Let $$0 \leq a \leq x \leq 100$$ and $$f(x) = \mid x - a \mid + \mid x - 100 \mid + \mid x - a - 50\mid$$. Then the maximum value of f(x) becomes 100 when a is equal to
x>=a, so |x-a| = x-a
x<100, so |x-100| = 100-x
f(x) = (x-a) + (100-x) + |x-a-50| =100
or, |x-a-50| = a
From the graph we can can see that when x=a then
|x-a-50|=a
or, a= 50
Similarly when x=a+100
|x-a-50|=a
or, a= 50
So value of a is 50 when f(x) is 100.
Let $$f(x)$$ be a quadratic polynomial in $$x$$ such that $$f(x) \geq 0$$ for all real numbers $$x$$. If f(2) = 0 and f( 4) = 6, then f(-2) is equal to
$$f(x) \geq 0$$for all real numbers $$x$$, so D<=0
Since f(2)=0 therefore x=2 is a root of f(x)
Since the discriminant of f(x) is less than equal to 0 and 2 is a root so we can conclude that D=0
Therefore f(x) = $$a\left(x-2\right)^2$$
f(4)=6
or, 6 = $$a\left(x-2\right)^2$$
a= 3/2
$$f\left(-2\right)=\ -\dfrac{3}{2}\left(-4\right)^2=24$$
Suppose for all integers x, there are two functions f and g such that $$f(x) + f (x - 1) - 1 = 0$$ and $$g(x ) = x^{2}$$. If $$f\left(x^{2} - x \right) = 5$$, then the value of the sum f(g(5)) + g(f(5)) is
Given,
$$f\left(x\right)+f\left(x-1\right)=1$$ ...... (1)
$$f\left(x^2-x\right)=5$$ ...... (2)
$$g\left(x\right)=x^2$$
Substituting x = 1 in (1) and (2), we get
f(0) = 5
f(1) + f(0) = 1
f(1) = 1 - 5 = -4
f(2) + f(1) = 1
f(2) = 1 + 4 = 5
f(n) = 5 if n is even and f(n) = -4 if n is odd
f(g(5)) + g(f(5)) = f(25) + g(-4) = -4 + 16 = 12
Let r be a real number and $$f(x) = \begin{cases}2x -r & ifx \geq r\\ r &ifx < r\end{cases}$$. Then, the equation $$f(x) = f(f(x))$$ holds for all real values of $$x$$ where
When x< r
f(x) = r
f(x) = f(f(x))
r = f(r)
r= 2r-r
r=r
When x>=r
f(x) = 2x-r
f(x) = f(f(x))
2x-r = f(2x-r)
2x-r = 2(2x-r) - r
2x-r = 4x-3r
or, x=r
Therefore x<= r
For any real number x, let [x] be the largest integer less than or equal to x. If $$\sum_{n=1}^N \left[\dfrac{1}{5} + \dfrac{n}{25}\right] = 25$$ then N is
It is given,
$$\Sigma_{n=1}^N\ \left[\dfrac{1}{5}+\dfrac{n}{25}\right]=25$$
$$\Sigma_{n=1}^N\ \left[\dfrac{5+n}{25}\right]=25$$
For n = 1 to n = 19, value of function is zero.
For n = 20 to n = 44, value of function will be 1.
44 = 20 + n - 1
n = 25 which is equal to given value.
This implies N = 44
If $$f(x)=x^{2}-7x$$ and $$g(x)=x+3$$, then the minimum value of $$f(g(x))-3x$$ is:
Now we have :
$$f(g(x))-3x$$
so we get f(x+3)-3x
= $$\left(x+3\right)^2-7\left(x+3\right)-3x$$
=$$x^2-4x-12$$
Now minimum value of expression = $$-\frac{D}{4a}$$ $$ \frac{\left(4ac-b^2\right)}{4a}$$
We get - (16+48)/4
= -16
Let $$f(x)=x^{2}+ax+b$$ and $$g(x)=f(x+1)-f(x-1)$$. If $$f(x)\geq0$$ for all real x, and $$g(20)=72$$. then the smallest possible value of b is
$$f\left(x\right)=\ x^2+ax+b$$
$$f\left(x+1\right)=x^2+2x+1+ax+a+b$$
$$f\left(x-1\right)=x^2-2x+1+ax-a+b$$
$$ g(x)=f(x+1)-f(x-1)= 4x+2a$$
Now $$g(20) = 72$$ from this we get $$a = -4$$ ; $$f\left(x\right)=x^2-4x\ +b$$
For this expression to be greater than zero it has to be a perfect square which is possible for $$b\ge\ 4$$
Hence the smallest value of 'b' is 4.
The number of real-valued solutions of the equation $$2^{x}+2^{-x}=2-(x-2)^{2}$$ is:
The graphs of $$2^{x}+2^{-x} and 2-(x-2)^{2}$$ never intersect. So, number of solutions=0.
Alternate method:
We notice that the minimum value of the term in the LHS will be greater than or equal to 2 {at x=0; LHS = 2}. However, the term in the RHS is less than or equal to 2 {at x=2; RHS = 2}. The values of x at which both the sides become 2 are distinct; hence, there are zero real-valued solutions to the above equation.
The area of the region satisfying the inequalities $$\mid x\mid-y\leq1,y\geq0$$ and $$y\leq1$$ is
The area of the region contained by the lines $$\mid x\mid-y\leq1,y\geq0$$ and $$y\leq1$$ is the white region.
Total area = Area of rectangle + 2 * Area of triangle = $$2+\left(\frac{1}{2}\times\ 2\times\ 1\right)\ =3$$
Hence, 3 is the correct answer.
In a group of 10 students, the mean of the lowest 9 scores is 42 while the mean of the highest 9 scores is 47. For the entire group of 10 students, the maximum possible mean exceeds the minimum possible mean by
Let x(1) be the least number and x(10) be the largest number. Now from the condition given in the question , we can say that
x(2)+x(3)+x(4)+........x(10)= 47*9=423...................(1)
Similarly x(1)+x(2)+x(3)+x(4)................+x(9)= 42*9=378...............(2)
Subtracting both the equations we get x(10)-x(1)=45
Now, the sum of the 10 observations from equation (1) is 423+x(1)
Now the minimum value of x(10) will be 47 and the minimum value of x(1) will be 2 . Hence minimum average 425/10=42.5
Maximum value of x(1) is 42. Hence maximum average will be 465/10=46.5
Hence difference in average will be 46.5-42.5=4 which is the correct answer
The area, in sq. units, enclosed by the lines $$x=2,y=\mid x-2\mid+4$$, the X-axis and the Y-axis is equal to
The required figure is a trapezium with vertices A(0,0), B(2,0), C(2,4) and D(0,6)
AB = 2 BC = 4 and AD = 6
Area of trapezium = $$\frac{1}{2}\left(sum\ of\ the\ opposite\ sides\right)\cdot height$$ = $$\frac{1}{2}\left(4+6\right)\cdot2\ =\ 10$$
If $$f(x+y)=f(x)f(y)$$ and $$f(5)=4$$, then $$f(10)-f(-10)$$ is equal to
The given function is equivalent to f(x) = $$a^x$$
Given, f(5) = 4
=> $$a^5=4=>\ a=4^{\frac{1}{5}}$$
=> f(x) = $$4^{\frac{x}{5}}$$
f(10) - f(-10) = 16 - 1/16 = 15.9375
If $$f(5+x)=f(5-x)$$ for every real x, and $$f(x)=0$$ has four distinct real roots, then the sum of these roots is
Let 'r' be the root of the function. It follows that f(r) = 0. We can represent this as $$f\left(r\right)=f\left\{5-\left(5-r\right)\right\}$$
Based on the relation: $$f\left(5-x\right)=f\left(5+x\right)$$; $$f\left(r\right)=f\left\{5-\left(5-r\right)\right\}=f\left\{5+\left(5-r\right)\right\}$$
$$\therefore\ f\left(r\right)=f\left(10-r\right)$$
Thus, every root 'r' is associated with another root '(10-r)' [these form a pair]. For even distinct roots, in this case four, let us assume the roots to be as follows: $$r_1,\ \left(10-r_1\right),\ r_2,\ \left(10-r_2\right)$$
The sum of these roots = $$r_1\ +\left(10-r_1\right)+\ r_2+\ \left(10-r_2\right)\ =\ 20$$
Hence, Option D is the correct answer.
In how many ways can a pair of integers (x , a) be chosen such that $$x^{2}-2\mid x\mid+\mid a-2\mid=0$$ ?
$$x^{2}-2\mid x\mid+\mid a-2\mid=0$$
where x>= 0 and x>=2
$$x^2-2x+a-2\ =0$$ Using quadratic equation we have $$x=\ 1+\sqrt{\ 3-a}\ and\ x=1-\sqrt{\ 3-a}$$ Only two integer values are possible
a=2 and a=3. So corresponding "x" values are x=1 and a=3, x=2 and a=2, x=0 and a=2
where x>=0 and x<2
Applying the above process we get x=1 and a=1
where x<0 and x>=2 we get a=3 and x=-1 , a=2 and x=-2
where x<0 and x<2 we get a=1 and x=-1
Hence there are total 7 values possible
Consider a function f satisfying f (x + y) = f (x) f (y) where x,y are positive integers, and f(1) = 2. If f(a + 1) +f (a + 2) + ... + f(a + n) = 16 (2$$^n$$ - 1) then a is equal to
f (x + y) = f (x) f (y)
Hence, f(2)=f(1+1)=f(1)*f(1)=2*2=4
f(3)=f(2+1)=f(2)*f(1)=4*2=8
f(4)=f(3+1)=f(3)*f(1)=8*2=16
.......=> f(x)=$$2^x$$
Now, f(a + 1) +f (a + 2) + ... + f(a + n) = 16 (2$$^n$$ - 1)
On putting n=1 in the equation we get, f(a+1)=16 => f(a)*f(1)=16 (It is given that f (x + y) = f (x) f (y))
=> $$2^a$$*2=16
=> a=3
For any positive integer n, let f(n) = n(n + 1) if n is even, and f(n) = n + 3 if n is odd. If m is a positive integer such that 8f(m + 1) - f(m) = 2, then m equals
Assuming m is even, then 8f(m+1)-f(m)=2
m+1 will be odd
So, 8(m+1+3)-m(m+1)=2
=> 8m+32-$$m^2-m$$=2
=> $$m^2-7m-30=0$$
=> m=10,-3
Rejecting the negative value, we get m=10
Assuming m is odd, m+1 will be even.
then, 8(m+1)(m+2)-m-3=2
=> 8($$m^2+3m+2$$)-m-3=2
=> $$8m^2+23m+11=0$$
Solving this, m = -2.26 and -0.60
Hence, the value of m is not integral. Hence this case will be rejected.
The number of the real roots of the equation $$2 \cos (x(x + 1)) = 2^x + 2^{-x}$$ is
$$2 \cos (x(x + 1)) = 2^x + 2^{-x}$$
The maximum value of LHS is 2 when $$\cos (x(x + 1))$$ is 1 and the minimum value of RHS is 2 using AM $$\geq$$ GM
Hence LHS and RHS can only be equal when both sides are 2. For LHS, cosx(x+1)=1 => x(x+1)=0 => x=0,-1
For RHS minimum value, x=0
Hence only one solution x=0
Let S be the set of all points (x, y) in the x-y plane such that $$\mid x \mid + \mid y \mid \leq 2$$ and $$\mid x \mid \geq 1.$$ Then, the area, in square units, of the region represented by S equals

Sum of the area of region I and II is the required area.

Now, required area = $$\ 4\times\frac{\ 1}{2}\times\ 1\times\ 1$$ = 2
Let f be a function such that f (mn) = f (m) f (n) for every positive integers m and n. If f (1), f (2) and f (3) are positive integers, f (1) < f (2), and f (24) = 54, then f (18) equals
Given, f(mn) = f(m)f(n)
when m= n= 1, f(1) = f(1)*f(1) ==> f(1) = 1
when m=1, n= 2, f(2) = f(1)*f(2) ==> f(1) = 1
when m=n= 2, f(4) = f(2)*f(2) ==> f(4) = $$[f(2)]^2$$
Similarly f(8) = f(4)*f(2) =$$[f(2)]^3$$
f(24) = 54
$$[f(2)]^3$$ * $$[f(3)]$$ = $$3^3*2$$
On comparing LHS and RHS, we get
f(2) = 3 and f(3) = 2
Now we have to find the value of f(18)
f(18) = $$[f(2)]$$ * $$[f(3)]^2$$
= 3*4=12
Let f(x)= $$\max(5x, 52-2x^2)$$, where x is any positive real number. Then the minimum possible value of f(x)
The minimum value of the function will occur when the expressions inside the function are equal.
So, 5$$x$$ = $$52 - 2x^2$$
or, $$2x^2 + 5x - 52$$ = 0
On solving, we get $$x$$ = 4 or $$-\dfrac{13}{2}$$
But, it is given that $$x$$ is a positive number.
So, $$x$$ = 4
And the minimum value = 5*4 = 20
Hence, 20 is the correct answer.
Let f(x) = min ($${2x^{2},52-5x}$$) where x is any positive real number. Then the maximum possible value of f(x) is
f(x) = min ($${2x^{2},52-5x}$$)
The maximum possible value of this function will be attained at the point in which $$2x^2$$ is equal to $$52-5x$$.
$$2x^2 = 52-5x$$
$$2x^2+5x-52=0$$
$$(2x+13)(x-4)=0$$
=> $$x=\frac{-13}{2}$$ or $$x = 4$$
It has been given that $$x$$ is a positive real number. Therefore, we can eliminate the case $$x=\frac{-13}{2}$$.
$$x=4$$ is the point at which the function attains the maximum value. $$4$$ is not the maximum value of the function.
Substituting $$x=4$$ in the original function, we get, $$2x^2 = 2*4^2= 32$$.
f(x) = $$32$$.
Therefore, 32 is the right answer.
If $$f(x + 2) = f(x) + f(x + 1)$$ for all positive integers x, and $$f(11) = 91, f(15) = 617$$, then $$f(10)$$ equals
$$f(x + 2) = f(x) + f(x + 1)$$
As we can see, the value of a term is the sum of the 2 terms preceding it.
It has been given that $$f(11) = 91$$ and $$f(15) = 617$$.
We have to find the value of $$f(10)$$.
Let $$f(10)$$ = b
$$f(12)$$ = b + 91
$$f(13)$$ = 91 + b + 91 = 182 + b
$$f(14)$$ = 182+b+91+b = 273+2b
$$f(15)$$ = 273+2b+182+b = 455+3b
It has been given that 455+3b = 617
3b = 162
=> b = 54
Therefore, 54 is the correct answer.
Let $$f(x) = x^{2}$$ and $$g(x) = 2^{x}$$, for all real x. Then the value of f[f(g(x)) + g(f(x))] at x = 1 is
$$f[f(g(1)) + g(f(1))]$$
= $$f[f(2^1) + g(1^2)]$$
= $$f[f(2) + g(1)]$$
= $$f[2^2 + 2^1]$$
= $$f(6)$$
= $$6^2 = 36$$
If $$f_{1}(x)=x^{2}+11x+n$$ and $$f_{2}(x)=x$$, then the largest positive integer n for which the equation $$f_{1}(x)=f_{2}(x)$$ has two distinct real roots is
$$f_{1}(x)=x^{2}+11x+n$$ and $$f_{2}(x) = x$$
$$f_{1}(x)=f_{2}(x)$$
=> $$x^{2}+11x+n = x$$
=> $$ x^2 + 10x + n = 0 $$
=> For this equation to have distinct real roots, b$$^2$$-4ac>0
$$ 10^2 > 4n$$
=> n < 100/4
=> n < 25
Thus, largest integral value that n can take is 24.
If f(ab) = f(a)f(b) for all positive integers a and b,
then the largest possible value of f(1) is
f(1 * 1) = f(1)f(1)
=> f(1) = f(1)f(1)
=> f(1) = 0 or f(1) = 1
Hence maximum value of f(1) is 1
Let $$f(x) =2x-5$$ and $$g(x) =7-2x$$. Then |f(x)+ g(x)| = |f(x)|+ |g(x)| if and only if
$$|f(x)+ g(x)| = |f(x)| + |g(x)|$$ if and only if
case 1: $$f(x) \geq 0$$ and $$g(x) \geq 0$$
<=> $$ 2x-5 \geq 0 $$ and $$7-2x \geq 0$$
<=> $$ x \geq \frac{5}{2}$$ and $$ \frac{7}{2} \geq x$$
<=> $$\frac{5}{2}\leq x\leq\frac{7}{2}$$
case 2: $$f(x) \leq 0$$ and $$g(x) \leq 0$$
<=> $$ 2x-5 \leq 0 $$ and $$7-2x \leq 0$$
<=> $$ x \leq \frac{5}{2}$$ and $$ \frac{7}{2} \leq x$$
So x<=5/2 and x>=7/2 which is not possible.
Hence, answer is
<=> $$\frac{5}{2}\leq x\leq\frac{7}{2}$$
$$f(x) = \dfrac{5x+2}{3x-5}$$ and $$g(x) = x^2 - 2x - 1$$, then the value of $$g(f(f(3)))$$ is
$$f(3) = \frac{15 + 2}{9 - 5} = \frac{17}{4}$$
$$f(f(3)) = \frac{5*17/4 + 2}{3*17/4 - 5} = \frac{93/4}{31/4} = \frac{93}{31} = 3$$
$$g(f(f(3))) = 3^2 - 3*2 - 1 = 2$$
Let $$f(x)\neq0$$ for any 'x' be a function satisfying $$f(x)f(y) = f(xy)$$ for all real x, y. If $$f(2) = 4$$, then what is the value of $$f(\frac{1}{2})$$?
$$f(1)^2$$ = f(1) => f(1) = 1
f(2)*(f(1/2) = f(1) => 4x = 1
So, f(1/2) = 1/4
Suppose, the seed of any positive integer n is defined as follows:
seed(n) = n, if n < 10
seed(n) = seed(s(n)), otherwise, where s(n) indicates the sum of digits of n.
For example, seed(7) = 7,
seed(248) = seed(2 + 4 + 8) = seed(14) = seed (1 + 4) = seed (5) = 5 etc.
How many positive integers n, such that n < 500, will have seed (n) = 9?
For seed (n) = 9, all the numbers below 500 must have a digit sum of 9.
These numbers are all divisible by 9.
So total number of numbers below 500 and divisible by 9 is 55.
Find the sum $$\sqrt{1+\frac{1}{1^2}+\frac{1}{2^2}}+\sqrt{1+\frac{1}{2^2}+\frac{1}{3^2}} +....+ \sqrt{1+\frac{1}{2007^2}+\frac{1}{2008^2}}$$
Consider the first term:
$$\sqrt{1+1/1^2+1/2^2}$$ = $$\sqrt{9/4}$$ = 3/2
Second term: $$\sqrt{1+1/2^2+1/3^2}$$ = $$\sqrt{49/36}$$ = 7/6
First term + Second term = 3/2 + 7/6 = (9+7)/6 = 16/6 = 8/3 = 3 - 1/3
.
.
Required sum = 2008 - 1/2008
Let $$f(x) = ax^2 + bx + c$$, where a, b and c are certain constants and $$a \neq 0$$ ?
It is known that $$f(5) = - 3f(2)$$. and that 3 is a root of $$f(x) = 0$$.
What is the other root of f(x) = 0?
f(3) = 9a + 3b + c = 0 f(5) = 25a + 5b + c
f(2) = 4a + 2b + c
f(5) = -3f(2) => 25a + 5b + c = -12a -6b -3c
=> 37a + 11b + 4c = 0 --> (1)
4(9a + 3b + c) = 36a + 12b + 4c = 0 --> (2)
From (1) and (2), a - b = 0 => a = b
=> c = -12a
The equation is, therefore, $$ax^2 + ax - 12a = 0 => x^2 + x - 12 = 0$$
=> -4 is a root of the equation.
Let $$f(x) = ax^2 + bx + c$$, where a, b and c are certain constants and $$a \neq 0$$ ?
It is known that f(5) = - 3f(2). and that 3 is a root of f(x) = 0.
What is the value of a + b + c?
f(3) = 9a + 3b + c = 0 f(5) = 25a + 5b + c
f(2) = 4a + 2b + c
f(5) = -3f(2) => 25a + 5b + c = -12a -6b -3c
=> 37a + 11b + 4c = 0 --> (1)
4(9a + 3b + c) = 36a + 12b + 4c = 0 --> (2)
From (1) and (2), a - b = 0 => a = b
=> c = -12a
The equation is, therefore, $$ax^2 + ax - 12a = 0 => x^2 + x - 12 = 0$$
a + b + c = a + a - 12a = -10a.
But the value of a is not given. Therefore, the value cannot be determined.
A function $$f (x)$$ satisfies $$f(1) = 3600$$, and $$f (1) + f(2) + ... + f(n) =n^2f(n)$$, for all positive integers $$n > 1$$. What is the value of $$f (9)$$ ?
According to given conditions we get f(2)=f(1)/3 , then f(3)=f(1)/6, then f(4)=f(1)/10 , then f(5)=f(1)/15 .
We can see the pattern here that the denominator goes on increasing from 3,3+3,6+4,10+5,15+6,.. so for the f(9) the denominator will be same as 15+6+7+8+9=45 .
So f(9)=3600/45 = 80
Directions for the following two questions:
Let $$a_1= p$$ and $$b_1 = q$$, where p and q are positive quantities.
Define $$a_n = pb_{n-1} , b_n = qb_{n-1}$$ , for even n > 1. and $$a_n = pa_{n-1} , b_n = qa_{n-1}$$ , for odd n > 1.
Which of the following best describes $$a_n + b_n$$ for even n?
$$a_n + b_n$$ for even n = $$p*b_{n-1} + q*b_{n-1}$$
= $$(p+q)*b_{n-1}$$
$$b_{n-1} = q*a_{n-2} = qp*b_{n-3}$$
= $$q^2*p*a_{n-4} = q^2p^2*b_{n-5}$$
.
.
= $$(qp)^{n/2-1}*b_1 = (qp)^{n/2-1}*q$$
So, $$a_n + b_n$$ = $$q(pq)^{(n/2) -1}(p+q)$$
Directions for the following two questions:
Let $$a_1= p$$ and $$b_1 = q$$, where p and q are positive quantities.
Define $$a_n = pb_{n-1} , b_n = qb_{n-1}$$ , for even n > 1. and $$a_n = pa_{n-1} , b_n = qa_{n-1}$$ , for odd n > 1.
If p = 1/3 and q = 2/3 , then what is the smallest odd n such that $$a_n+b_n < 0.01$$?
$$a_{n} + b_{n}$$ (n is odd) = $$p^{\frac{n+1}{2}}*q^{\frac{n-1}{2}} + p^{\frac{n -1}{2}}*q^{\frac{n+1}{2}}$$ = $$(p + q)pq^{\frac{n-1}{2}}$$
Substituting the values of p and q we get
$$a_{n} + b_{n}$$ = $$(\frac{2}{9})^{\frac{n-1}{2}}$$
Now substitute the values of n and check.
We can see that the lowest value of n for which
$$a_{n} + b_{n}$$ < .01 is 9
Directions for the following two questions:
Let S be the set of all pairs (i, j) where 1 <= i < j <= n , and n >= 4 (i and j are natural numbers). Any two distinct members of S are called “friends” if they have one constituent of the pairs in common and “enemies” otherwise.
For example, if n = 4, then S = {(1, 2), (1, 3), (1, 4), (2, 3), (2, 4), (3, 4)}. Here, (1, 2) and (1, 3) are friends, (1,2) and (2, 3) are also friends, but (1,4) and (2, 3) are enemies.
For general n, consider any two members of S that are friends. How many other members of S will be common friends of both these members?
For n, the number of elements in set S is $$^nC_2$$.
Lets say the 2 friends are (x,a) and (y,a)
These two friends have 3 numbers in total and 1 common element(say a) (as both elements cannot be exactly same)
They have 2 non common elements(x, y)
The number of common friends is formed by the non-common elements of the friends (x,y) + the number of elements in the set which have the common element other than the two friends (a,c), (a,d) and so on = 1 + (n-1 - 2) = n-2.
For the example in question, if the friends are (1,2) and (1,3), then common friends are (2,3) and all other elements with 1
All elements with 1 = n-1= 3 which are (1,2) (1,3) (1,4) excluding the friends (1,2) and (1,3) only 1 other friend is common. Hence it is 1+(n-1)-2=n-2
Directions for the following two questions:
Let S be the set of all pairs (i, j) where 1 <= i < j <= n , and n >= 4 (i and j are natural numbers). Any two distinct members of S are called “friends” if they have one constituent of the pairs in common and “enemies” otherwise.
For example, if n = 4, then S = {(1, 2), (1, 3), (1, 4), (2, 3), (2, 4), (3, 4)}. Here, (1, 2) and (1, 3) are friends, (1,2) and (2, 3) are also friends, but (1,4) and (2, 3) are enemies.
For general n, how many enemies will each member of S have?
Any ordered pair has 2 elements => There are n-2 elements that are not present in the ordered pair.
The number of enemies of any ordered pair is all the ordered pairs in the set formed using the numbers other than these two elements = $$^{n-2}C_2$$ = $$1/2 * (n^2 - 5n + 6)$$.
The graph of y - x (on the y axis) against y + x (on the x axis) is as shown below. (All graphs in this question are drawn to scale and the same scale and the same scale has been used on each axis.)
Which of the following shows the graph of y against x?
For a normal graph with y and x-axis, the equation of the line passing through the origin is y =mx where m is the slope of the line.
m is +ve if the angle made by the line with the x-axis is < $$90^{\circ\ }$$
$$\therefore\ $$ The equation of the line in the given graph would be y-x = k( y+ x) since the axes are y-x and y+x and the line is passing through the origin.
k > 1 because the angle is greater than 45$$^{\circ\ }$$
$$y=\dfrac{x\left(k+1\right)}{1-k}$$
Since k>1
Therefore y<0 for x>-1 and y>0 for x<-1
Option d correctly satisfy this condition
Let $$f(x) = \text{max }(2x + 1, 3 - 4x)$$, where $$x$$ is a real number. Then the minimum possible value of $$f(x)$$ is:
The minimum value is obtained when 2x+1 = 3-4x => 6x = 2 => x = 1/3
So, f((x) = 2*1/3 + 1 = 5/3
If $$a_1 = 1$$ and $$a_{n+1} - 3a_n + 2 = 4n$$ for every positive integer n, then $$a_{100}$$ equals
Using given condition we find $$a_2$$ = 5 and $$a_3$$ = 21 and so on.
We see that the numbers are of form $$3^n-(2*n)$$
So for 100 we have $$3^{100}-200$$
In the X-Y plane, the area of the region bounded by the graph of |x+y| + |x-y| = 4 is
If the moduli are removed, the equations formed are
x+y+x-y = 4 => x=2
x+y-x+y = 4 => y =2
-x-y+x-y = 4 => y=-2
-x-y-x+y = 4 => x=-2
The area enclosed by these equations is a square with vertices at (2,2), (-2,2), (-2,-2), (2,-2) as shown in figure.
The required area = 4*4 = 16
Let g(x) be a function such that g(x+1) + g(x-1) = g(x) for every real x. Then for what value of p is the relation g(x+p) = g(x) necessarily true for every real x?
According to given condition we have , g(x+1) = -g(x-1) + g(x)
Putting x=x+1 we get g(x+2) = g(x+1) - g(x) = -g(x-1)
Putting x=x+2 we get g(x+3)=-g(x)
Similarly g(x+4)=-g(x+1), g(x+5)=-g(x+2)=-g(x+1) + g(x) and g(x+6) = g(x+1)-g(x+2)=g(x).
So p=6.
If $$f(x)=x^3-4x+p$$ , and f(0) and f(1) are of opposite signs, then which of the following is necessarily true
[CAT 2004]
f(1) = 1-4+p = p-3
f(0) = p
Since they are of opposite signs, p(p-3) < 0
=> 0 < p < 3
Let $$ y = \frac{1}{2+\frac{1}{3+\frac{1}{2+\frac{1}{3+…}}}}$$. Then y equals?
$$ y = \frac{1}{2+\frac{1}{3+\frac{1}{2+\frac{1}{3+…}}}}$$
which is equal to $$ y = \frac{1}{2+\frac{1}{3+y}} $$ solving we get
$$ y = \frac{3+y}{7+2y} $$ we get
$$2y^2+6y-3=0$$ .
Solution of this equation is $$\frac{\sqrt{15}-3}{2}$$.
Let $$f(x) = ax^2 - b|x|$$ , where a and b are constants. Then at x = 0, f(x) is
$$f(x) = ax^2 - b|x|$$. When $$x=0, f(x) = 0$$
When $$a > 0$$ and $$b < 0$$,
For x > 0, $$f(x) = ax^2 - bx$$, will be greater than 0 as $$ax^2 > 0$$ and $$bx<0$$ as $$b$$ is negative and $$x$$ is positive.
For x < 0, $$f(x) = ax^2 + bx$$ will again be greater than 0 as $$ax^2 >0$$ and $$bx>0$$ as both $$b$$ and $$x$$ are negative.
Therefore, the function $$f(x)$$ is positive when $$x<0$$ and when $$x>0$$ but becomes 0 when $$x=0$$.
Therefore, for $$a > 0$$ and $$b < 0$$, f(x) will attain its minimum value at $$x = 0$$.
If $$\frac{a}{b+c}=\frac{b}{a+c} =\frac{c}{b+a} =r$$, then r cannot take any value except
a = r(b+c)
b = r(a+c)
c = r(a+b)
On adding all the equations,
a+b+c = 2r(a+b+c)
If r = 1/2, a+b+c = a+b+c (valid)
If r = -1, a+b+c = -2(a+b+c) => a+b+c = 0 => b+c = -a and a/(b+c) = a/(-a) = -1 (valid)
So, r can take the values 1/2 or -1
Directions for the following two questions:
Answer the questions on the basis of the information given below.
$$f_1(x) = x$$ if $$0 \leq x \leq 1$$ $$f_1(x) = 1$$ if x >= 1 $$f_1(x) = 0$$ otherwise
$$f_2(x) = f_1(-x)$$ for all x
$$f_3(x) = -f_2(x)$$ for all x
$$f_4(x) = f_3(-x)$$ for all x
How many of the following products are necessarily zero for every x:
$$f_1(x)f_2(x), f_2(x)f_3(x), f_2(x)f_4(x)$$
Checking for different values of x . Suppose x= -0.5 we get
$$f_1(x)f_2(x) = 0*0.5 = 0$$
$$f_2(x)f_4(x) = 0.5*0 = 0$$ .
But $$f_2(x)f_3(x)$$ is not equal to zero.
Hence two functions are necessarily equal to zero and two products given above are equal to zero.
Directions for the following two questions:
Answer the questions on the basis of the information given below.
$$f_1(x) = x$$ if $$0 \leq x \leq 1$$ $$f_1(x) = 1$$ if x >= 1 $$f_1(x) = 0$$ otherwise
$$f_2(x) = f_1(-x)$$ for all x
$$f_3(x) = -f_2(x)$$ for all x
$$f_4(x) = f_3(-x)$$ for all x
Which of the following is necessarily true?
Relation between f3 and f1 would be
$$f_3(x) = -f_1(-x)$$.
Put x= -x we get
$$f_3(-x) = -f_1(x)$$ so multiply by -1 we get
$$-f_3(-x) = f_1(x)$$.
The number of non-negative real roots of $$2^x - x - 1 = 0$$ equals
$$2^x - x - 1 = 0$$ for this equation only 0 and 1 i.e 2 non-negative solutions are possible. Or we can plot the graph of $$2^x$$ and x+1 and determine the number of points of intersection and hence the solutin.
When the curves $$y = log_{10}x$$ and $$y = x^{-1}$$ are drawn in the x-y plane, how many times do they intersect for values $$x \geq 1$$ ?
Graph of logx goes on increasing in 1st quadrant and graph of 1/x goes no decreasing with both intersecting only once
Let g(x) = max(5 - x, x + 2). The smallest possible value of g(x) is
Smallest possible value would be at 5-x = x+2 i.e. x= 1.5 as shown
Substituting we get smallest value as 3.5.
The function f(x) = |x - 2| + |2.5 - x| + |3.6 - x|, where x is a real number, attains a minimum at
f(x) = |x - 2| + |2.5 - x| + |3.6 - x|
For x belonging to (-infinity to 2), f(x) = 2-x + 2.5-x + 3.6-x = 8.1-3x
This attains the minimum value at x=2. Value = 2.1
For x belonging to (2 to 2.5), f(x) = x-2 + 2.5-x + 3.6-x = 4.1-x
Attains the minimum value at x = 2.5. Value = 1.6
For x belonging to (2.5 to 3.6), f(x) = x-2 + x-2.5 + 3.6-x = x-0.9
Attains the minimum at x=2.5, value = 1.6
For x > 3.6, f(x) = x-2+x-2.5+x-3.6 = 3x - 8.1
Attains the minimum at x= 3.6, value = 2.7
So, min value of the function is 1.6 at x=2.5
Consider the following two curves in the x-y plane:
$$y = x^3 + x^2 + 5$$
$$y = x^2 + x + 5$$
Which of following statements is true for $$-2 \leq x \leq 2$$ ?
Equate the 2 equations we get value of x = 1 and -1 . Also we notice that there is intersection at x=0 . hence D
Suppose for any real number x, [x] denotes the greatest integer less than or equal to x. Let L(x, y) = [x] + [y] + [x + y] and R(x, y) = [2x] + [2y]. Then it is impossible to find any two positive real numbers x and y for which
Consider different values of x and y:
x = -1.5 and y = -1.5; x = 1.5 and y = -1.5; x = -1.5 and y = 1.5; x = 1.5 and y = 1.5.
For these possibilities, options A,B and C gets satisfied , but it is impossible to find any two positive real numbers x and y for which L(x, y) > R(x, y).
In the above table, for suitably chosen constants a, b and c, which one of the following best describes the relation between y and x?
y=a+bx is a linear function and clearly the function shown in the table is not linear.
Lets take option B:
Suppose $$y=f(x)=a+bx+cx^2$$
f(1)=4 => a+b+c=4 -- (1)
f(2)=8 => a+2b+4c=8 -- (2)
f(3)=14 => a+3b+9c=14 -- (3)
Let us solve the equations and see if $$f(4), f(5),f(6)$$ also satisfy the given equation.
(2)-(1) => b+3c=4
(3)-(2) => b+5c=6
This gives c=1 and b=1 ==> a=2
So, $$f(x)=2+x+x^2$$
$$f(4)=2+4+4^2 = 22$$
$$f(5)=2+5+5^2 = 32$$
$$f(6)=2+6+6^2 = 44$$
As all the three also satisfy the numbers given in the table, it can be inferred that the relationship between x and y is quadratic and the correct option is option (b)
The area bounded by the three curves |x+y| = 1, |x| = 1, and |y| = 1, is equal to:
|x| = 1 and |y| = 1 form a square of area = 2*2 = 4 sq units
|x+y| = 1 forms a set of parallel lines cutting the axes at (1,0), (0,1), (-1,0) and (0,-1). The graph is as shown:
The area bounded by the three curves is 2*2 - 1/2*1*1*2 = 4 - 1 = 3 sq units
The set of all positive integers is the union of two disjoint subsets:
{f(1), f(2),.....f(n), ...} and {g(1),g(2).... ,g(n).....}, where f(1) < f(2) <.....< f(n)..., and g(1) < g(2) < ..... < g(n) ...,and
g(n) = f(f(n))+1 for all n >= 1. What is the value of g(1)?
The union of the two sets is the set of positive integers. Also, given the increasing nature of elements, either f(1) or g(1) must be equal to 1. If g(1) = 1, then f(f(1)) =0 which cannot be under the given conditions.
Hence, f(1) = 1
g(1) = f(f(1))+1 = 2
For all non-negative integers x and y, f(x, y) is defined as below:
f(0, y) = y + 1
f(x + 1, 0) = f(x, 1)
f(x+ 1, y+ 1)= f(x, f(x+ 1, y))
Then, what is the value of f(1,2)?
For f(1,2). First consider x=0 and y=1 and use 3rd given equation, we get f(0,f(1,1)) now for f(1,1) take x=0 and y=0 we get f(0,f(1,0)), for f(1,0) which we use 2nd equation we get f(0,1) whose value is 2. So we have f(0,f(1,0))= f(0,2) whose value is 3 then put this in f(0,f(1,1)) we get f(0,3) we get as 4
Directions for the next 2 questions:
For a real number x, let
$$f(x) = 1/(1+x),$$ if $$x$$ is non-negative
$$f(x) = 1+x,$$ if $$x$$ is negative
$$f^n(x) = f(f^{n-1}(x)), n = 2, 3.....$$
What is the value of the product, $$f(2) f^2(2)f^3(2) f^4(2)f^5(2)$$?
f(2) = 1/3
$$f^2(2)$$ = f(1/3) = 3/4
$$f^3(2)$$ = f(3/4) = 4/7
$$f^4(2)$$ = f(4/7) = 7/11
$$f^5(2)$$ = f(7/11) = 11/18
So, product = 1/18
Directions for the next 2 questions:
For a real number x, let
$$f(x) = 1/(1+x),$$ if $$x$$ is non-negative
$$f(x) = 1+x,$$ if $$x$$ is negative
$$f^n(x) = f(f^{n-1}(x)), n = 2, 3.....$$
r is an integer 2. Then, what is the value of $$f^{r-1}(-r) + f^r(-r) + f^{r+1}(-r)$$?
f(-2) = -1
$$f^2(-2)$$ = f(f(-2)) = f(-1) = 0
$$f^3(-2)$$ = f(f(-2)) = f(0) = 1
So, sum = 0
Directions for the next 2 questions:
For real numbers x, y, let
f(x, y) = Positive square-root of (x + y), if $$(x + y)^{0.5}$$ is real
f(x, y) = $$(x + y)^2$$; otherwise
g(x, y) = $$(x + y)^2$$, if $$\sqrt{(x + y)}$$ is real
g(x, y) = $$- (x + y)$$ otherwise
Which of the following expressions yields a positive value for every pair of non-zero real numbers (x, y)?
f(x,y) is always non-negative because $$(x+y)^2$$ is always positive
g(x, y) = $$(x + y)^2$$, if $$\sqrt{(x + y)}$$ is real = Always positive
g(x, y) = $$- (x + y)$$ otherwise = Always positive because this happen when (x+y)<0 and -(x+y) is always greater than zero.
f(x,y)+g(x,y) = Always positive
Directions for the next 2 questions:
For real numbers x, y, let
f(x, y) = Positive square-root of (x + y), if $$(x + y)^{0.5}$$ is real
f(x, y) = $$(x + y)^2$$; otherwise
g(x, y) = $$(x + y)^2$$, if $$\sqrt{(x + y)}$$ is real
g(x, y) = $$- (x + y)$$ otherwise
Under which of the following conditions is f(x, y) necessarily greater than g(x, y)?
When both x and y are less than -1, g(x,y) > 2 and f(x,y) > 4 and $$f(x,y) = g(x,y)^2$$
So, f(x,y) > g(x,y)
Directions for the next 3 questions:
Given below are three graphs made up of straight-line segments shown as thick lines. In each case choose the answer as:
a) if f(x)=3f(-x)
b) if f(x)= -f(-x)
c) if f(x) = f(-x)
d) if 3f(x) = 6f(-x), for x >= 0
In the given graph, the value of y is constant irrespective of the value of x. Hence value of y would be same for a particular x and -x.
Hence f(x) = f(-x)
Directions for the next 3 questions:
Given below are three graphs made up of straight-line segments shown as thick lines. In each case choose the answer as:
a) if f(x)=3f(-x)
b) if f(x)= -f(-x)
c) if f(x) = f(-x)
d) if 3f(x) = 6f(-x), for x >= 0
In this graph, f(-1) = 1 and f(1) = 2 and since the two lines pass origin, their values increase linearly.
3f(x) = 6f(-x)
Directions for the next 3 questions:
Given below are three graphs made up of straight-line segments shown as thick lines. In each case choose the answer as:
a) if f(x)=3f(-x)
b) if f(x)= -f(-x)
c) if f(x) = f(-x)
d) if 3f(x) = 6f(-x), for x >= 0
In this graph, we can see that the graph on LHS of y axis is symmetrical to the graph on RHS of y axis about origin.
Hence f(x) = -f(-x)
Directions for the next 3 questions: For three distinct real positive numbers x, y and z, let
f(x, y, z) = min (max(x, y), max (y, z), max (z, x))
g(x, y, z) = max (min(x, y), min (y, z), min (z, x))
h(x, y, z) = max (max(x, y), max(y, z), max (z, x))
j(x, y, z) = min (min (x, y), min(y, z), min (z, x))
m(x, y, z) = max (x, y, z)
n(x, y, z) = min (x, y, z)
Which of the following is necessarily greater than 1?
From the given functions we can make out that function h and m give max value , function n and j give min value , function f and g give middle value. From this equation (f(x, y, z) + h(x, y, z)-g(x, y, z))/j(x, y, z) , numerator is always max value and denominator is min value . So this will always be greater than 1 .
Suppose x>y>z
f(x,y,z) = y
g(x,y,z) = y
h(x,y,z) = x
j(x,y,z) = z
Option d = x/z >1
Directions for the next 3 questions: For three distinct real positive numbers x, y and z, let
f(x, y, z) = min (max(x, y), max (y, z), max (z, x))
g(x, y, z) = max (min(x, y), min (y, z), min (z, x))
h(x, y, z) = max (max(x, y), max(y, z), max (z, x))
j(x, y, z) = min (min (x, y), min(y, z), min (z, x))
m(x, y, z) = max (x, y, z)
n(x, y, z) = min (x, y, z)
Which of the following expressions is necessarily equal to 1?
From the given functions we can make out that function h and m give max value , function n and j give min value , function f and g give middle value. So according to equation (f(x, y, z)- m(x, y, z))/(g(x, y, z)-h(x,y, z)) , value of numerator and denominator is equal and hence ratio is equal to 1.
Suppose x>y>z
f(x,y,z) = y
g(x,y,z) = y
h(x,y,z) = x
j(x,y,z) = z
Option a = (y-x)/(y-x) = 1
Directions for the next 3 questions: For three distinct real positive numbers x, y and z, let
f(x, y, z) = min (max(x, y), max (y, z), max (z, x))
g(x, y, z) = max (min(x, y), min (y, z), min (z, x))
h(x, y, z) = max (max(x, y), max(y, z), max (z, x))
j(x, y, z) = min (min (x, y), min(y, z), min (z, x))
m(x, y, z) = max (x, y, z)
n(x, y, z) = min (x, y, z)
Which of the following expressions is indeterminate?
From the given functions we can make out that function h and m give max value , function n and j give min value , function f and g give middle value.So in option B , j cancels out n and h cancels out m . So the denominator becomes 0 and value is indeterminable.
Suppose x>y>z
f(x,y,z) = y
g(x,y,z) = y
h(x,y,z) = x
j(x,y,z) = z
m(x,y,z) = x
n(x,y,z) = z
The denominator of the second option becomes 0, hence making it indeterminate.
For two positive integers a and b define the function h(a,b):as the greatest common factor (G.C.F) of a, b. Let A be a set of n positive integers. G(A), the GCF of the elements of set A is computed by repeatedly using the function h.
The minimum number of times h is required to be used to compute G is:
Let p and q be any two elements of the set A.
For the computation of the GCF of elements of the set A, we can replace both p and q by just the GCF(p,q) and the result is unchanged.
So, for every application of the function h, we are reducing the number of elements of the set A by 1. (In this case two numbers p and q are replaced by one number GCF(p,q)).
Expanding this concept further, the minimum number of times the function h should be called is n-1
DIRECTIONS for the following questions: These questions are based on the situation given below: In each of the questions a pair of graphs F(x) and F1(x) is given. These are composed of straight-line segments, shown as solid lines, in the domain $$x\epsilon (-2, 2)$$.
choose the answer as
a. If F1(x) = - F(x)
b. if F1(x) = F(- x)
c. if F1(x) = - F(- x)
d. if none of the above is true
The correct relation between the two is: F(x) = | F1(x) |
So, all the three options a), b) and c) can be ruled out. Option d) is the correct answer.
DIRECTIONS for the following questions: These questions are based on the situation given below: In each of the questions a pair of graphs F(x) and F1(x) is given. These are composed of straight-line segments, shown as solid lines, in the domain $$x\epsilon (-2, 2)$$.
choose the answer as
a. If F1(x) = - F(x)
b. if F1(x) = F(- x)
c. if F1(x) = - F(- x)
d. if none of the above is true
The value of F(x) for x < 0 is the same as the value of F1(x) for x > 0.
So, F1(x) = F(-x)
Option b) is the correct answer.
DIRECTIONS for the following questions: These questions are based on the situation given below: In each of the questions a pair of graphs F(x) and F1(x) is given. These are composed of straight-line segments, shown as solid lines, in the domain $$x\epsilon (-2, 2)$$.
choose the answer as
a. If F1(x) = - F(x)
b. if F1(x) = F(- x)
c. if F1(x) = - F(- x)
d. if none of the above is true
The value of F(x) for x > 0 is the same as the value of F1(x) for x < 0.
So, F1(x) = F(-x)
Option b) is the correct answer.
DIRECTIONS for the following questions: These questions are based on the situation given below: In each of the questions a pair of graphs F(x) and F1(x) is given. These are composed of straight-line segments, shown as solid lines, in the domain $$x\epsilon (-2, 2)$$.
choose the answer as
a. If F1(x) = - F(x)
b. if F1(x) = F(- x)
c. if F1(x) = - F(- x)
d. if none of the above is true
F(0) = 1 ; F1(0) = -1
F(1) = 0 ; F1(-1) = 0
F(2) = -1 ; F1(-2) = 1
=> F1(x) = -F(-x).
DIRECTIONS for the following questions:
These questions are based on the situation given below: A robot moves on a graph sheet with x and y-axes. The robot is moved by feeding it with a sequence of instructions. The different instructions that can be used in moving it, and their meanings are: Instruction Meaning GOTO(x,y) move to point with coordinates (x, y) no matter where you are currently WALKX(P) Move parallel to the x-axis through a distance of p, in the positive direction if p is positive, and in the negative direction if p is negative WALKY(P) Move parallel to the y-axis through a distance of p, in the positive direction if p is positive, and in the negative direction if p is negative.
The robot reaches point (6, 6) when a sequence of three instructions is executed, the first of which is a GOTO(x, y) instruction, the second is WALKX(2) and the third is WALKY(4). What are the values of x and y?
Before, the third instruction, the point on which the robot is present is (6,2).
Before, the second instruction, the point on which the robot is present is (4,2).
Hence, the values of x and y are 4 and 2 respectively.
DIRECTIONS for the following questions:
These questions are based on the situation given below: A robot moves on a graph sheet with x and y-axes. The robot is moved by feeding it with a sequence of instructions. The different instructions that can be used in moving it, and their meanings are: Instruction Meaning GOTO(x,y) move to point with coordinates (x, y) no matter where you are currently WALKX(P) Move parallel to the x-axis through a distance of p, in the positive direction if p is positive, and in the negative direction if p is negative WALKY(P) Move parallel to the y-axis through a distance of p, in the positive direction if p is positive, and in the negative direction if p is negative.
The robot is initially at (x, y), x > 0 and y < 0. The minimum number of instructions needed to be executed to bring it to the origin (0,0) if you are prohibited from using the GOTO instruction is:
WALKX(-x) and WALKY(y) are the commands to be used for the robot to reach origin in any order.
Hence, the answer is 2.
DIRECTIONS for the following questions: These questions are based on the situation given below: Let x and y be real numbers
f(x, y) = | x + y |
F(f(x, y)) = -f(x, y)
G(f(x, y)) = -F(f(x, y))
Which of the following statements is true?
f(x,y) = |x+y|
F(f(x,y)) = -f(x,y) = -|x+y|
G(f(x,y)) = -F(f(x,y)) = |x+y|
Option A: F(f(x, y)) . G(f(x, y)) = -F(f(x, y)) . G(f(x, y)) =>LHS = -|x+y|$$^2$$, RHS = |x+y|$$^2$$ Hence false.
Option B: F(f(x, y)) . G(f(x, y)) > -F(f(x, y)) . G(f(x, y)), Since, LHS is smaller than RHS. False
Option C: F(f(x, y)) . G(f(x, y)) $$\neq $$ G(f(x, y)) . F(f(.x, y)), Here LHS=RHS. Hence false.
Option D:
=> G(f(x,y)) + F(f(x,y)) = 0
f(x,y) = f(-x,-y)
=> G(f(x,y)) + F(f(x,y)) + f(x,y) = f(-x.-y)
DIRECTIONS for the following questions: These questions are based on the situation given below: Let x and y be real numbers
f(x, y) = | x + y |
F(f(x, y)) = -f(x, y)
G(f(x, y)) = -F(f(x, y))
What is the value of f(G(f(1, 0)), f(F(f(1, 2)), G(f(1, 2))))?
F(f(x,y)) = -f(x,y)
G(f(x,y)) = -F(f(x,y)) = f(x,y)
G(f(1,0)) = 1
F(f(1,2)) = -3
G(f(1,2)) = 3
f(F(f(1,2)),G(f(1,2))) = 0
f(G(f(1, 0)), f(F(f(1, 2)), G(f(1, 2)))) = 1 + 0 = 1
DIRECTIONS for the following questions: These questions are based on the situation given below: Let x and y be real numbers
f(x, y) = | x + y |
F(f(x, y)) = -f(x, y)
G(f(x, y)) = -F(f(x, y))
Which of the following expressions yields $$x^2$$ as its result?
F(f(x,-x)) = 0 and G(f(x,-x)) = 0
F(f(x,x)) = -2x and G(f(x,x)) = 2x
F(f(x,x)).G(f(x,x)) = -$$4x^2$$
$$\log_216$$ = 4
=> $$\frac{-F(f(x,x)).G(f(x,x))}{\log_216}$$ = $$x^2$$
Answer the questions based on the following information. A, S, M and D are functions of x and y, and they are defined as follows.
$$A(x, y)=x + y$$
$$S(x, y)=x-y$$
$$M(x, y)=xy$$
$$D(x,y)=\frac{x}{y}$$. $$y\neq0$$
What is the value of $$M(M(A(M(x, y),S(y, x)),x),A(y, x))$$for $$x=2, y=3$$?
Given expression can be reduced to
M ( x(xy+y-x) , (y+x) )
Or x(x+y)(xy+y-x)
After putting value of x and y , expression will reduce to a value = 70.
Answer the questions based on the following information. A, S, M and D are functions of x and y, and they are defined as follows.
$$A(x, y)=x + y$$
$$S(x, y)=x-y$$
$$M(x, y)=xy$$
$$D(x,y)=\frac{x}{y}$$. $$y\neq0$$
What is the value of $$S[M(D(A(a, b), 2), D(A(a, b), 2)), M(D(S(a, b), 2), D(S(a, b), 2))]$$?
Given expression can be reduced to:
$$S[M(\frac{a+b}{2}),(\frac{a+b}{2})), M((\frac{a- b}{2}, (\frac{a-b}{2})]$$
= $$S[(\frac{(a+b)}{2})^2, (\frac{(a-b)}{2})^2]$$
= $$(\frac{a+b}{2})^2 - (\frac{(a-b)}{2})^2 $$
= ab
A function can sometimes reflect on itself, i.e. if y = f(x), then x = f(y). Both of them retain the same structure and form. Which of the following functions has this property?
Putting y as x and x as y in given options, only options B satisfies the function property as follows.
x = $$\frac{2y+3}{3y-2}$$
or 3xy - 2x = 2y+3
or y(3x-2) = 2x+3
or $$y = \frac{2x+3}{3x-2}$$
What is the value of k for which the following system of equations has no solution:
2x-8y = 3 and kx +4y = 10
On solving both equations, we will get $$x = \frac{23}{2+2k}$$
now for having no solutions to system 2+2k should be 0.
Hence k=-1
If $$y = f(x)$$ and $$f(x) = \frac{(1-x)}{(1 + x)}$$, which of the following is true?
Among all options only D satisfies the given equations as follows:
$$f(y) = \frac{1-y}{1+y}$$
and for x:
$$y + xy = 1-x$$
$$x(1+y) = 1-y$$
$$x= \frac{1-y}{1+y}$$
Hence $$x=f(y)$$
Let Y = minimum of {(x+2), (3-x)}. What is the maximum value of Y for 0 <= x <=1?
For x<0 ; y=x+2
for 0<x<$$\frac{1}{2}$$ ; $$y=x+2$$
for $$x>\frac{1}{2}$$ ; $$y=3-x$$
Hence, $$y$$ attains its maxima at $$x=\frac{1}{2}$$ i.e. $$y$$ = 2.5
Frequently Asked Questions
Yes, Functions and Graphs are key topics in CAT 2026 Quant. They test conceptual clarity, interpretation skills, and application of mathematical relationships.
For CAT 2026, focus on domain and range, types of functions, graphs of standard functions, and transformations.
Questions are usually moderate but can become tricky when combined with graphs or real-life data interpretation scenarios.
Focus on understanding graph behaviour, practice sketching functions, and solve mixed problems regularly to build confidence.
Yes, mock tests are essential for CAT 2026 as they help improve time management, accuracy, and familiarity with exam patterns.
Cracku is a reliable platform offering topic-wise practice, previous year questions, and mock tests tailored for CAT 2026 aspirants.
Typically, 1-3 questions may appear in CAT 2026 from Functions, Graphs, or Statistics, either standalone or mixed with other topics.