// convert degrees to redians
function deg2rad(angle){
    return angle/180*Math.PI;
}

// convert radians to degrees
function rad2deg(angle){
    return angle/Math.PI*180;
}

// sinh() and cosh() functions not readily available in JaveScript
function sinh(c) {
	var p = Math.pow(Math.E, c);
	return (p-1/p)/2;
};
function cosh(c) {
	var p = Math.pow(Math.E, c);
	return (p+1/p)/2;
};