ACOS

Purpose:

Calculates the inverse cosine of any expression.

Syntax:

ACOS(val)

val

-

A scalar, series or table.

Returns:

A scalar, series, or table.

Example:

acos(-1..0.01..1);gridhv;griddot

 

 

image\acospic01.gif

 

 

displays the inverse cosine from 1 to 1.

Example:

acos(0)

 

returns 1.570796 or π/2.

Example:

acos(-2..0.1..2)

 

returns a 41 point complex series.

Remarks:

The inverse cosine is defined as:

 

image\acos01.gif

 

for all complex z. The function is multi-valued and this definition places the branch cut in the complex plane at [-∞, -1] and [1, ∞].

 

For |x| > 1, acos(x) returns a complex result.

 

The function calculates in radians unless degrees are specified with the SETDEGREE function.

See Also:

ACOSH

ASEC

ASIN

COS

COSH

GACOS

SETDEGREE

SETRADIAN

TRIGONOMETRIC FUNCTIONS