Ice-Cream Cone problem - Volume in Spherical Coord

masterchiefo
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Homework Statement


S is the sphere of equation x2 + y2 + z2 = 10z and C the cone of equation
z= sqrt(3*( x2 + y2)) . The axes are measured
centimeters.
R of sphere = 5
D = 10

Total height is 10 cm

Illustrate the solid E bounded by the C cone and the sphere S and calculate its volume using the details
Spherical.

Homework Equations

The Attempt at a Solution


To find phi:
x=0
z= sqrt(3*( x2 + y2))
z= sqrt(3*( 02 + y2))
z= y*sqrt(3)

y= 3 <== I picked 3, could of picked any number, its just to find the Z and then find the angle.
z= 3*sqrt(3)

tan(phi)=3/(3*sqrt(3))
phi = pi/6 ===30degree

Theta = 2*pi

$=integral
2*pi$0 pi/6$0 10*cos(phi)$0 p2*sin(phi) dp dphi dtheta

229.074cm3
 
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I didn't check the value of your integral but it looks like it is set up correctly. Why give a decimal instead of exact answer?
 
LCKurtz said:
I didn't check the value of your integral but it looks like it is set up correctly. Why give a decimal instead of exact answer?
I am used to give decimal as my teacher always ask for that.
 
LCKurtz said:
I didn't check the value of your integral but it looks like it is set up correctly. Why give a decimal instead of exact answer?

masterchiefo said:
I am used to give decimal as my teacher always ask for that.

Nevertheless, what you should routinely do is give the exact answer if it is practical, and at the very end put the decimal approximation. For example, if the exact answer is ##\frac {\sqrt 3} 5## you could write it like this:
$$\text{Your Variable }=\frac {\sqrt 3} 5 \approx .3464$$That would be correct, good form, and would satisfy your teacher.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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