sin
See the current Perl documentation for sin.
Here is our local, out-dated (pre-5.6) version:
sin - return the sin of a number
sin EXPR
sin
Returns the sine of
EXPR (expressed in radians). If
EXPR is omitted, returns sine of
$_.
For the inverse sine operation, you may use the POSIX::asin()
function, or use this relation:
sub asin { atan2($_[0], sqrt(1 - $_[0] * $_[0])) }