There are several different definitions of conical coordinates defined by Morse and Feshbach (1953), Byerly (1959), Arfken (1970), and Moon and Spencer (1988). The system defined in the Wolfram Language is
(1)
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(2)
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(3)
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where . Byerly (1959) uses a system which is essentially the same coordinate system as above, but replacing with , with , and with . Moon and Spencer (1988) use instead of .
The above equations give
(4)
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(5)
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(6)
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The scale factors are
(7)
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(8)
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(9)
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The Laplacian is
(10)
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The Helmholtz differential equation is separable in conical coordinates.