Let f(x)=tan^-1 x. Then, f'(x)+f''(x) = ...

Let `f(x)=tan^-1 x.` Then, `f'(x)+f''(x) = 0,` when `x` is equal to

A

(a) `0`

B

(b) `1`

C

(c) `i`

D

(d) `-i`

Verified by Experts

The correct Answer is:

B

Similar Questions

Explore conceptually related problems

If f(x) = (x-1)/(x+1) , then f(2x) is equal to

If f(x) = 1/(1-x) , then f(f(f(x))) is equal to

Let f(x) be a polynomial of degree four having extreme values at x=1 and x=2. IF lim_(xto0) [1+(f(x))/x^2]=3 , then f(2) is equal to

Let f(x) =x^(p) cos (1/x) , when x ne 0 and f(x)=0 , when x=0 . Then f(x) will be differentiable at x=0 , if

From mean value theoren : f(b)-f(a)=(b-a)f^(prime)(x_1); a lt x_1 lt b if f(x)=1/x , then x_1 is equal to

If f(x) = log ((1+x)/(1-x)) , then f((2x)/(1+x^(2))) is equal to

If f(x)=int_(-1)^(x)|t|dt , then for any x ge0,f(x) is equal to

If f(1)=3 , f'(1)=2 , then d/(dx) {logf(e^x+2x)} at x=0 is equal to........