Volume using spherical coordinates

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SUMMARY

The discussion focuses on calculating the volume of a solid bounded by a cone and two spheres using spherical coordinates. The integral presented is V = ∫₁³ ∫₀²π ∫₋π/₄⁽⁻⁾π/₂ ρ² sin(φ) dp dφ dθ, which is correct for the specified bounds. The transformation from Cartesian to spherical coordinates is essential, with the relations x = r sin(φ) cos(θ), y = r sin(φ) sin(θ), and z = r cos(φ) being highlighted. The angles for the integration limits are derived from the geometric constraints of the cone and spheres.

PREREQUISITES
  • Spherical coordinates transformation
  • Understanding of triple integrals
  • Knowledge of geometric shapes: cones and spheres
  • Familiarity with LaTeX for mathematical expressions
NEXT STEPS
  • Study the derivation of volume integrals in spherical coordinates
  • Learn about the geometric interpretation of spherical coordinates
  • Explore the application of triple integrals in different coordinate systems
  • Practice converting Cartesian equations to spherical coordinates
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Students and professionals in mathematics, physics, and engineering who are working with volume calculations in three-dimensional space, particularly those using spherical coordinates.

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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 doesn'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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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?
 

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