cos - cosine function

- NAME
- SYNOPSIS
- DESCRIPTION

# NAME

cos - cosine function

# SYNOPSIS

cos EXPR

cos

# DESCRIPTION

Returns the cosine of EXPR (expressed in radians). If EXPR is omitted, takes cosine of `$_`.

For the inverse cosine operation, you may use the `Math::Trig::acos()` function, or use this relation:

        sub acos { atan2( sqrt(1 - $_[0] * $_[0]), $_[0] ) }

cos - cosine function