ACOS

Purpose:

Calculates the inverse cosine of any expression.

ACOS(val)

val

A scalar, series or table.

A scalar, series, or table.

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

$image\acospic01.gif$

displays the inverse cosine from –1 to 1.

acos(0)

returns 1.570796 or π/2.

acos(-2..0.1..2)

returns a 41 point complex series.

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.