Deriving the Volume of a Sphere Using Spherical Coordinates

AI Thread Summary
The discussion focuses on deriving the volume of a sphere using spherical coordinates, emphasizing the need for clear integral limits and their corresponding angles. Participants express a desire for a detailed explanation of how the differential volume element (dV) is derived, particularly the role of the angle phi. The transformation from Cartesian to spherical coordinates is highlighted, with specific equations provided for x, y, and z in terms of rho, phi, and theta. The importance of understanding which integral limit corresponds to each angle is stressed, as existing resources like Mathworld lack clarity on this aspect. A comprehensive derivation with visual aids is requested to enhance understanding.
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I just need a really good derivation of it using spherical coordinates, like the integral limits.

pictures might help
 
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sssddd said:
I just need a really good derivation of it using spherical coordinates, like the integral limits.

pictures might help

\iiint\limits_E{\rho}^2\,\sin{\phi}\,d\phi\,d\rho\,d\theta\quad E:\left\{0\leq\phi\leq\pi;\quad 0\leq\rho\leq r;\quad 0\leq\theta\leq 2\pi\right\}
 
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actually i was more interested in how you derived the d phi(that other angle thing) part

Like which integrant belongs to which. Mathworld doesn't show too much of that, the math part I get but I would like to know which angle belong to which. Since there are 3 sets of integral limits, then there should 3 of them, so which belongs which accoring to the equation cavoy posted
 
sssddd said:
actually i was more interested in how you derived the d phi(that other angle thing) part

Like which integrant belongs to which. Mathworld doesn't show too much of that, the math part I get but I would like to know which angle belong to which. Since there are 3 sets of integral limits, then there should 3 of them, so which belongs which accoring to the equation cavoy posted

From cartesian to spherical coordinates:

x=\rho\cos{\phi}\cos{\theta}

y=\rho\cos{\phi}\sin{\theta}

z=\rho\sin{\phi}

...then use the Jacobian to get the equivalent of dV in terms of phi, theta, and rho.
 
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