ACOS — Arccosine function

ACOS(X) computes the arccosine of X (inverse of COS(X)).

RESULT = ACOS(X)

X The type shall either be REAL with a magnitude that is less than or equal to one - or the type shall be COMPLEX.

The return value is of the same type and kind as X. The real part of the result is in radians and lies in the range 0 \leq \Re \acos(x) \leq \pi.



program test_acos

  real(8) :: x = 0.866_8

  x = acos(x)

end program test_acos

Name Argument Return type Standard
ACOS(X) REAL(4) X REAL(4) Fortran 77 and later
DACOS(X) REAL(8) X REAL(8) Fortran 77 and later

Fortran 77 and later, for a complex argument Fortran 2008 or later

Elemental function