# Homework Help: Convert a derivative back to original function

1. Apr 28, 2007

### Ishtar

The problem statement, all variables and given/known data

f'(x) = 5x^2 + 7x -3

The attempt at a solution

i divided 5 by 3 to get 5/3
added 1 to exponent of 5x^2
made 7x to 7x^2 and -3 to -3x

to get

f(x) = 5/3 x^ 3 + 7x^2 - 3x

i get this answer, but is there and other way to get the original function and other possible answers (or a helpfull website related to this)

Last edited: Apr 28, 2007
2. Apr 28, 2007

### christianjb

The middle term is 7/2 x^2.

Note that you could also add any number to your expression and you would still get the same derivative, because, e.g. d/dx 42 =0.

You're actually doing 'integration', though you may not know it yet. Wikipediate or Google it.

3. Apr 28, 2007

### HallsofIvy

You said you "made 7x to 7x^2 and -3 to -3x" but you didn't do that in your answer.

Believe it or not, derivatives and "anti- derivatives" are calculus, not "pre"- calculus. I'm going to move this to the calculus homework forum.

4. Apr 28, 2007