6.21 ATAN — Arctangent function

Description:

ATAN(X) computes the arctangent of X.

Standard:

F77 and later

Class:

Elemental function

Syntax:

RESULT = ATAN(X)

Arguments:

X	The type shall be REAL(*).

Return value:

The return value is of type REAL(*) and it lies in the range - \pi / 2 \leq \atan (x) \leq \pi / 2.

Example:

          program test_atan
            real(8) :: x = 2.866_8
            x = atan(x)
          end program test_atan
     

Specific names:

Name	Argument	Return type	Standard
DATAN(X)	REAL(8) X	REAL(8)	F77 and later

See also:

Inverse function: TAN