Converts an angle from radians to degrees.
angle in radians
angle in degrees
var d = rad2deg( 3.141592653589793/2.0 ); // returns 90.0
var d = rad2deg( -3.141592653589793/4.0 ); // returns -45.0
var d = rad2deg( NaN ); // returns NaN
Converts an angle from radians to degrees.