Volume using spherical coordinates

In summary, the problem involves finding the volume of a solid that lies inside a cone and between two spheres. The integral needs to be set up in spherical coordinates, and the equation for the region can be restated to include the new coordinates. The angle values can be found using the transformation relations from Cartesian to polar.
  • #1
lap_tech
1
0
Hello. Here is the problem I am currently having difficulties with:
"find the volume of the solid that lies inside the cone z^2 = 3x^2 + 3y^2 and between spheres x^2 + y^2 + z^2 = 1 and x^2 + y^2 + z^2 = 9"

I know that this integral needs to be setup in spherical coordinates... Here is the integral I came up with. I'm not sure if it is correct though...
v = integral from 1 to 3 integral from 0 to 2pie integral from pie/4 to pie/2
p^2 sin(phi) dp d(phi) d(theta)
does this seem correct?

let me try to put it in LaTeX format... (sorry if it dosen't work..)

[tex]V=\int_1^3 \int_0^\Pi \int_\frac{\pi}{4}^\frac{\pi}{2} \rho^2 \sin\phi dpd\phi d\theta[/tex]
 
Last edited:
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  • #2
Where do you get your angle values from??

When doing coordinate changes, it is always helpful to restate your equations in terms of your new coordinates.
First, the general transformation relations from Cartesian to polar:
[tex]x=r\sin\phi\cos\theta,y=r\sin\phi\sin\theta,z=r\cos\phi, 0\leq\theta\leq{2}\pi,0\leq\phi\leq\pi,0\leq{r}[/tex]

Now, restatement of your equations delineating your region:
[tex]r^{2}=1, r^{2}=9,\tan^{2}\phi=\frac{1}{3}[/tex]

What does this tell you?
 

What is the formula for finding volume using spherical coordinates?

The formula for finding volume using spherical coordinates is V = ∫∫∫ ρsinφ dρ dφ dθ, where ρ is the radial distance, φ is the polar angle, and θ is the azimuthal angle.

How is the volume element expressed in spherical coordinates?

The volume element in spherical coordinates is expressed as dV = ρsinφ dρ dφ dθ.

Can the volume of any solid be found using spherical coordinates?

Yes, the volume of any solid can be found using spherical coordinates as long as the shape can be defined by a radius and two angles.

What are the advantages of using spherical coordinates to find volume?

Spherical coordinates are advantageous when working with objects that have spherical or cylindrical symmetry, as the equations are simpler and the integration can be easier to evaluate.

How are spherical coordinates related to Cartesian coordinates?

Spherical coordinates are related to Cartesian coordinates through the following equations:
x = ρsinφcosθ
y = ρsinφsinθ
z = ρcosφ
where x, y, and z are the Cartesian coordinates and ρ, φ, and θ are the spherical coordinates.

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