Question

For the function y=f(x), find f’(a)

Answer 1

-1/4

Explanation:

f(x) = 1/(x+1)

f(a) = 1/(a+1)

f'(a) = {(a+1)×d/da (1) - d/da (a+1) × 1}/(a+1)²

f'(a) = {(a+1)×0 - 1×1}/(a+1)²

f'(a) = (0-1)/(a²+2a+1)

f'(a) = -1/(1+2a+a²)

putting a = 1

f'(a) = -1/(1+2+1)

f'(a) = -1/4