all Python 3cmathfunction

cmath.tan()

trigonometry

The tangent of a complex argument. At π/2 it does not fail but returns a huge number, because pi/2 is inexact.

Syntax

cmath.tan(z)

Learners expect a division-by-zero error from tan(π/2), but neither math nor cmath gives one: pi/2 is slightly less than the true π/2, and the result is 1.633123935319537e+16. Check for proximity to the pole yourself. For an imaginary argument tan(ix) = i·tanh(x), so its modulus stays below one.

Examples

import cmath
print(cmath.tan(cmath.pi / 2))  # → (1.633123935319537e+16+0j)
print(cmath.tan(1j))  # → 0.7615941559557649j

See also

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