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arctan(z)

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3-d plot

Inverse trigonometric functions:

The function arctan is the inverse to the function tan. Hence w=arctan(z) gives all solutions to the equation z=tan(w). The inverse tangent function is multivalued with branch lines extending from +i and -i to infinity. The image shows the principal branch of the multi-valued function. The principal branch has the property arctan(0) = 0.