Volume in Spherical Coordinates

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SUMMARY

The volume element in spherical coordinates can be expressed as dV = r^2 sin(θ) dr dθ dφ. To derive this, one can either use a geometric approach by marking small increments Δr, Δθ, and Δφ or an analytic method by determining dx, dy, and dz in terms of r, θ, and φ. It is crucial to remember that the multiplication of differentials is anti-commutative, which affects the formulation of the volume element.

PREREQUISITES
  • Understanding of spherical coordinates and their parameters (r, θ, φ).
  • Familiarity with differential calculus and the concept of differentials.
  • Knowledge of geometric interpretations of volume in three-dimensional space.
  • Basic algebraic manipulation of trigonometric functions.
NEXT STEPS
  • Study the derivation of volume elements in different coordinate systems, such as cylindrical coordinates.
  • Learn about the Jacobian determinant in coordinate transformations.
  • Explore applications of spherical coordinates in physics, particularly in electromagnetism and fluid dynamics.
  • Investigate the properties of integrals in spherical coordinates, including triple integrals.
USEFUL FOR

Students studying calculus, physics enthusiasts, and anyone interested in advanced mathematical concepts related to volume calculations in spherical coordinates.

craigory
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Homework Statement



express a volume element dV= dx*dy*dz in spherical cooridnates.
 
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have a crack mate! any ideas?
 
Is it simply to convert x y and z into corresponding spherical coordinates (ie r cos θ etc)
 
One way to do this is geometric- given specific r, \theta, and \phi, mark off a small "\Delta r", "\Delta \theta", "\Delta \phi" about the point and caculate its volume.

Another is analytic- determine dx, dy, and dz in terms of r, \theta, \phi, dr, d\theta, and d\phi, then multiply- but remember that multiplcation of differentials is anti-commutative: a(r,\theta, \phi)drd\theta= -a(r, \theta, \phi)d\theta dr.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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