(Subscript[z, 1]^2 + Subscript[z, 2]^2) D[w[Subscript[z, 1], Subscript[z, 2]], Subscript[z, 2], Subscript[z, 2]] + 2 Subscript[z, 2] D[w[Subscript[z, 1], Subscript[z, 2]], Subscript[z, 2]] == 0 /; w[Subscript[z, 1], Subscript[z, 2]] == ArcTan[Subscript[z, 1], Subscript[z, 2]]

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2001-10-29