This is one of canvas uses. I will show some of canvas techniques in Delphi later.
Basically this program draws function that you enter and it is one of 4 main trigonometric functions if you enter a,b and c :
a*sin(b*x)+c
a*cos(b*x)+c
a*tg(b*x)+c
a*ctg(b*x)+c
Here is the picture :


And i uploaded just executable file !

Nice program dude, just doing about this in math at school

Thanks for the share bro. We can learn Trigonometric functions now.