- #1
trancefishy
- 75
- 0
i posted a question earlier, but, the heart of the matter has been narrowed down. this question is much more straightforward than the details in the other one. what i want to know is how to obtain the volume of a cylinder of radius r and height h by integration.
EASY. if you divide it into disks and add them up. no problem. i need the volume when it is divided into rectangles. as in, the cylinder is lying on it's side.
try and try i might, i always end up with either the square root of a negative number, or the entire integral turns out to equal zero.
also, even though i know the integral should equal pi r^2 h, i don't see how to get pi into the equation. the only way i can see to define the width of the rectangles is by using the pythagorean thereom on a general triangle on the sides of the cylinder. any insight into this would be greatly appreciated
EASY. if you divide it into disks and add them up. no problem. i need the volume when it is divided into rectangles. as in, the cylinder is lying on it's side.
try and try i might, i always end up with either the square root of a negative number, or the entire integral turns out to equal zero.
also, even though i know the integral should equal pi r^2 h, i don't see how to get pi into the equation. the only way i can see to define the width of the rectangles is by using the pythagorean thereom on a general triangle on the sides of the cylinder. any insight into this would be greatly appreciated