Returns the inverse cosine (arc cosine) of a Complex, with branch cuts outside the interval [-1,1] along the real axis.

Namespace: Imsl.Math
Assembly: ImslCS (in ImslCS.dll) Version: 6.5.0.0

Syntax

C#
public static Complex Acos(
	Complex z
)
Visual Basic (Declaration)
Public Shared Function Acos ( _
	z As Complex _
) As Complex
Visual C++
public:
static Complex Acos(
	Complex z
)

Parameters

z
Type: Imsl.Math..::.Complex
A Complex object.

Return Value

A newly constructed Complex initialized to the inverse (arc) cosine of the argument. The real part of the result is in the interval [0,\pi].

Remarks

Specifically, if z = x+iy,

\acos(\bar{z}) = \overline{\acos(z)}.

\acos(\pm 0 + i0) returns \pi/2 - i0.

\acos(-\infty + i\infty) returns 3 \pi/4 - i\infty.

\acos(+\infty + i\infty) returns \pi/4 - i\infty.

\acos(x + i\infty ) returns \pi/2 - i\infty, for finite x.

\acos(-\infty + iy) returns \pi- i\infty, for positive-signed finite y.

\acos(+\infty + iy) returns +0 - i\infty, for positive-signed finite y.

\acos(\pm \infty + i\NaN) returns \NaN \pm i\infty (where the sign of the imaginary part of the result is unspecified).

\acos(\pm 0 + i\NaN) returns \pi/2 + i\NaN.

\acos(\NaN + i\infty) returns \NaN - i\infty.

\acos(x + i\NaN) returns \NaN + i\NaN, for nonzero finite x.

\acos(\NaN + iy) returns \NaN + i\NaN, for finite y.

\acos(\NaN + i\NaN) returns \NaN + i\NaN.

See Also