Sign in
Please select an account to continue using cracku.in
↓ →
Join Our JEE Preparation Group
Prep with like-minded aspirants; Get access to free daily tests and study material.
If $$m$$ and $$n$$ respectively are the number of local maximum and local minimum points of the function $$f(x) = \int_0^{x^2} \frac{t^2 - 5t + 4}{2 + e^t} dt$$, then the ordered pair $$(m, n)$$ is equal to
Given,
$$f(x)=\int_0^{x^2}\frac{t^2-5t+4}{2+e^t}\,dt$$
Using Leibnitz rule,
$$f'(x)=\frac{x^4-5x^2+4}{2+e^{x^2}}\cdot2x$$
$$=\frac{2x(x^2-1)(x^2-4)}{2+e^{x^2}}$$
Since,
$$2+e^{x^2}>0$$
for all $$x$$, the critical points are obtained from
$$2x(x^2-1)(x^2-4)=0$$
Hence,
$$x=0,\pm1,\pm2$$
Now, checking sign changes of
$$x(x^2-1)(x^2-4)$$
we get:
- Increasing on
$$(-\infty,-2),\ (-1,0),\ (1,2)$$
- Decreasing on
$$(-2,-1),\ (0,1),\ (2,\infty)$$
Therefore,
- Local maxima occur at
$$x=-2,\ 0,\ 2$$
So,
$$m=3$$
- Local minima occur at
$$x=-1,\ 1$$
So,
$$n=2$$
Hence,
$$\boxed{(m,n)=(3,2)}$$
Create a FREE account and get:
Educational materials for JEE preparation