Use the limit definition of the derivative to find f′(x) if

1. f(x) = x^2 + 3x
2. f(x) = 1/x + 1

kk for number one i got
f'(x) = 2x+3

and for number two i got
f'(x) = -1/(x+1)(x+1)

can any one verify these, especially number 2.

2 answers

Just to clarify for number 2 the questions is f(x)= 1/(x+1)
do you mean f(x) = 1/(x + 1)?
if yes, then number 2 is correct.