# Math Help - Integral

1. ## Integral

I understand integrals for the most part...but not sure what to do here.

Find the particular antiderivative that satisfies the following conditions:
$p'(x)=80/x^3$; $p(7)=8$

I know that $p(x)=-40/x^2$, but not sure where to go from there.

2. Integrand = antiderivative + constant.

You forgot to put the constant, after that plug the initial conditions.

3. So it becomes $p(7)=-40/7^2 + C$,

which becomes $-40/49 + C$

I still have no idea where the 8 comes into play...i feel like im missing something quite basic here.

4. p(7)=8. Substitute that in and solve for C.

5. Plug it into what?

I feel like a fool.

6. Originally Posted by calculuslyfrustrated
Plug it into what?

I feel like a fool.
you got $p(7) = -\frac{40}{49} + c$ but from the initial condition, $p(7) = 8$. so $8 = -\frac{40}{49} + c$ and solve for c..