Thanks for your replies , i really wasn't expecting so many replies for my simple question.Because of your explanation in detail i understood it properly.Mathematically Alex is 100% right , because it really gives me a gradient of zero which is literally a straight line. I have changed my code and it gives me a sine curve but , it sticks to the top of the window but i hope that can be figured out . Once again thanks for the help and thanks for supporting the idea that g.drawLine(i,i,i,i) represents a point .Hopefully i ill be posting the code when its all done