Answer:
-1/4
Step-by-step 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
