Largest possible volume of a cylinder inscribed in a cone

Calculus!
Messages
20
Reaction score
0

Homework Statement



A right circular cylinder is inscribed in a cone with height h and base radius r. Find the largest possible volume of such a cylinder.

I'm just really confused on how to figure this one out. The equation for the volume of a cone is v = 1/3pi r^2h and the volume of a cylinder is v = pi r^2h. I just don't know how to use these two formuals in order to find a solution. Please help me. Thanks.
 
Physics news on Phys.org


Draw a picture. Draw a coordinate system so and two lines, one through (r, 0) and (0, h) and the other through (-r, 0) and (0, h). That represents your cone. What are the equations of the lines? A cylinder inside the cone is represented by a rectangle in your picture. What are the dimensions of that cylinder?
 


The problem didn't state any dimensions or equations for the cylinder or cone.
 


Calculus! said:
The problem didn't state any dimensions or equations for the cylinder or cone.

From your first post:
A right circular cylinder is inscribed in a cone with height h and base radius r. Find the largest possible volume of such a cylinder.

r and h are the dimensions of the cone. Follow Halls's suggestion to draw a picture and label the important points.
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...

Similar threads

Back
Top