UnVoiding

function TangentToCircle(fromx, fromy, cx, cy, r) {
	var canvas = document.getElementById('canvas1');
	var context = canvas.getContext('2d');
	var fi = 0;
	
	context.beginPath();
	
	if (fromx != cx && fromy != cy) {
		var length = Math.sqrt(Math.pow(fromx - cx, 2) + Math.pow(fromy - cy, 2));
		var a = Math.atan(r/length);