Ugh, calculus test tommorrow :frown:
A sphere of radius 4 cm is inscribed in a right circular cone. What is the least possible vlume of the cone?
Alright, so this are the equations I got. One of them is wrong, becasue I can't get the right answer.
V = 1/3 * pi * r^2 * h
So I find h in terms of r, and come out with ( Im not sure if this is right ) :
h = 4r/(r-4)
Plug that into the volume equation, take the derivative, set to 0 and I get:
r=6
therefore: h=12
therefore: V= 452.4
But, the back of the book says V = 536.17
A sphere of radius 4 cm is inscribed in a right circular cone. What is the least possible vlume of the cone?
Alright, so this are the equations I got. One of them is wrong, becasue I can't get the right answer.
V = 1/3 * pi * r^2 * h
So I find h in terms of r, and come out with ( Im not sure if this is right ) :
h = 4r/(r-4)
Plug that into the volume equation, take the derivative, set to 0 and I get:
r=6
therefore: h=12
therefore: V= 452.4
But, the back of the book says V = 536.17
Facebook
Twitter