A function in the [expr] command that computes the '''sine''' of an angle. The angle is expressed in radians.

Not to be confused with the theological concept [http://www.newadvent.org/cathen/14004b.htm].

The '''sine''' could be approximated by :

======
proc sine x {
    return [expr {1.2732396*$x - 0.4052847*$x*abs($x)}]
}
======

======
proc sinus x {

if {$x < 0} then {
    set sine [expr {$x*(1.27323954 + .405284735 * $x)}]
} else {
    set sine [expr {$x*(1.27323954 - 0.405284735 * $x)}]
}
if {$sine < 0} then {
    set sine [expr {$sine*(-0.225 * ($sine + 1) + 1)}]
} else {
    set sine [expr {$sine*(0.225 * ($sine - 1) + 1)}]
}
return $sine
}
======

<<categories>> Command | Function | Mathematics