- #1
- 1,395
- 0
basically what i need is to find the area of the ring
the with is dr and the radius is r
so pi*(r+dr)^2 - pi*(r)^2
so why the dA is that simple expression??
http://www.freeimagehosting.net/image.php?cce537487f.gif
the with is dr and the radius is r
so pi*(r+dr)^2 - pi*(r)^2
so why the dA is that simple expression??
http://www.freeimagehosting.net/image.php?cce537487f.gif