Sanjoy Guha

CAT Preparation Community 10y ago

Two curves y=x^2-6x+8 and y=-x^2+bx+c are in x-y plane.If maxima of one curve is minima of other curves, then what is the value of b?

5

Srikanth LingamneniFaculty 10y ago

Hi Sujoy, as the coefficient of $$x^2$$ in both the equations is positive, both equations will have only minima. Hence for no value of b, the maxima of one curve can be equal to the minima of the other curve.
Please go through our CC50 concept on Maxima and Minima of Quadratic equations.
https://cracku.in/cat/cc50/maxima-minima-quad-equations

Srikanth LingamneniFaculty 10y ago

@Sanjoy, You should be able to solve this problem easily by using the tips given in the CC50 concept. Give it a try.

Sanjoy Guha 10y ago

Sorry the 2nd equation is y=-x^2+bx+c.It's my typing mistake..

Ankit Rana 10y ago

Differentiate both equations and equate them to zero.
Curve one: 2x-6=0 i.e. x=6
Curve two: -2x+b=0. For x=6 obtained from above equation, we get b=6

aditya prakash 10y ago

b=0

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