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8.279 TANPI — Circular tangent function ¶

Description:

TANPI(X) computes \tan(\pi x) without performing an explicit multiplication by \pi. This is achieved through argument reduction where |x| = n + r with n an integer and 0 \leq r \le 1. Due to the properties of floating-point arithmetic, the useful range for X is defined by ABS(X) <= REAL(2,KIND(X))**DIGITS(X).

Standard:

Fortran 2023

Class:

Elemental function

Syntax:

RESULT = TANPI(X)

Arguments:

X	The type shall be REAL.

Return value:

The return value is of the same type and kind as X.

Example:

program test_tanpi
  real :: x = 0.0
  x = tanpi(x)
end program test_tanpi

See also:

ATANPI — Circular arc tangent function
TAN — Tangent function