# Thread: Finding the right points...

1. ## Finding the right points...

Volumes of solids of revolution:

Volume = 750 u^3
Distance between the two points = x and x+30 (they need to be 30 cm's apart)

Formula: $
V = \pi \int (75/x)^2 dx
$

I have to find that x =15.5 and x+30 = 45.5.

PS: there is slight error in the volume, it may be a little more, or less.

Any help?

2. Originally Posted by iphysics
Volumes of solids of revolution:

Volume = 750 u^3
Distance between the two points = x and x+30 (they need to be 30 cm's apart)

Formula: $
V = \pi \int (75/x)^2 dx
$

I have to find that x =15.5 and x+30 = 45.5.

PS: there is slight error in the volume, it may be a little more, or less.

Any help?
This is confusing. I don't know what the "Volume" equation is meant to say.

$\pi \int_{15.5}^{45.5} \left ( \frac{75}{x} \right ) ^2 ~dx$