Python 3.6+mathterm

math.tau

constants

The mathematical constant τ = 2π ≈ 6.283185307179586. Convenient in formulas where 2π keeps coming up.

Syntax

math.tau

Added in Python 3.6, so code that must run on older interpreters still writes 2 * math.pi. The equality math.tau == 2 * math.pi is exact rather than accidental: doubling a float loses no bits, so both constants round to the same double. The payoff is readability — tau/8 reads as one eighth of a full turn — not extra precision.

Examples

import math
print(math.tau)  # → 6.283185307179586
print(math.tau == 2 * math.pi)  # → True
print(math.tau / 4)  # → 1.5707... (π/2)
print(math.sin(math.tau))  # → ?  (значение зависит от системной libm — карточка учит наличию погрешности, а не её цифрам)
print(math.cos(math.tau))  # → 1.0
print(math.tau * 5)  # → 31.41592653589793

See also

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