swift trigonometric functions (cos, tan, arcsin, arcos, arctan)
<p>hello I have to differenciate calculations in degrees and I have the following code but I doesn't return me the exact values. The only one right is the value of sin90 in degree = 1</p>

<pre><code>//////***** DEGREES ******//////
var sinus = sin(90.0 * M_PI / 180)
var cosinus = cos(90 * M_PI / 180)
var tangent = tan(90 * M_PI / 180)

var arcsinus = asin(90 * M_PI / 180)
var arcosinus = acos(90 * M_PI / 180)
var arctangent = atan(90 * M_PI / 180)
</code></pre>

<p>What is the right operation to return the exact value for every operation in degree for cos, tan and their ARC functions? </p>