# Antiderivative of Log

• Jun 4th 2011, 07:22 PM
RezMan
Antiderivative of Log

Find f given that f''= $\frac{-3}{x^2}$, f'(3) =5, and f(1) =3.

I got this far:

f'= $\frac{3}{x} + 4$

f=3log(x)+ 4x + C = 3

so log((1)^3) + 4(1) + C =3

Am I on the right track? If so I don't quite know what to do next
• Jun 4th 2011, 07:35 PM
Prove It
Yes, looks good. Remember that log(1) = 0. Evaluate C.
• Jun 4th 2011, 07:40 PM
RezMan
Right! why do I keep forgetting these simple things

3logx + 4x -1 Thanks!