all Python 3cmathfunction

cmath.exp()

powers and logarithms

The exponential e**z for a complex z. Euler's formula is written with it: exp(i·φ) is a point on the unit circle.

Syntax

cmath.exp(z)

Euler's formula exp(iπ) = -1 does not hold exactly in floating point: you get (-1+1.2246467991473532e-16j), because pi is only an approximation of π. Compare with cmath.isclose and round before printing. Unlike math.exp, it accepts and returns complex; when the real part is too large it raises OverflowError instead of returning inf.

Examples

import cmath
z = cmath.exp(1j * cmath.pi)
print(z)  # → (-1+1.2246467991473532e-16j)
print(z == -1, cmath.isclose(z, -1))  # → False True

import cmath
try:
    cmath.exp(1000)
except OverflowError as e:
    print(type(e).__name__)  # → OverflowError

See also

Common errors

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