- #1
spec00
- 3
- 0
Hello dear colleagues!
Yesterday i was trying to proof the surface area of a sphere formula, then i got some problems. I know that something is seriously wrong in this concept, but i can't tell what exactly is wrong. Could you guys help me please?
I just thougt about a hollow sphere, then we can slice it up to little cylinders with infinitesimal height (like slicing some onion rings). If we add up these teeny weeny little parts, i thought that we could obtain the area of the sphere.
[tex]x^{2}+y^{2}=r^{2}[/tex]
[tex]\int(2*\pi*x)*dy[/tex]
[tex]2*pi*\int\sqrt{y^{2}-r^{2}}*dy[/tex]
But when i integrate over 0 to R and multiply all by 2, the result is not correct. What did i do wrong?
Thanks!
Yesterday i was trying to proof the surface area of a sphere formula, then i got some problems. I know that something is seriously wrong in this concept, but i can't tell what exactly is wrong. Could you guys help me please?
I just thougt about a hollow sphere, then we can slice it up to little cylinders with infinitesimal height (like slicing some onion rings). If we add up these teeny weeny little parts, i thought that we could obtain the area of the sphere.
[tex]x^{2}+y^{2}=r^{2}[/tex]
[tex]\int(2*\pi*x)*dy[/tex]
[tex]2*pi*\int\sqrt{y^{2}-r^{2}}*dy[/tex]
But when i integrate over 0 to R and multiply all by 2, the result is not correct. What did i do wrong?
Thanks!