Maximize volume of a cone

  • #1
A conical cup is to be made by joining the edges OA, OB of the sector of a circle of radius 8cm. What angle @ gives the cup of maximum volume?


I'm having trouble solving this question. This is what I have done so far

we know V=pi*r^2*h/3

r is given, so we need to put h in terms of @.
now by similar triangles we can take another slice, and compare
r/h=R/(h-1).... (h-1) is just the height of the triangle below the new slice
solving for h I get h=1/(1-R/r) now i'm unsure of what to do now, and how to get @ into the equation.


Anyways please let me know if i'm doing this question completely wrong or what not. Thanks for all your help
 

Answers and Replies

  • #2
Tide
Science Advisor
Homework Helper
3,076
0
r is not given! You're given the radius of the sector of the circle but that is not the same as the radius of the cone.
 
  • #3
184
0
a picture would help
 

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