Построить график функции: y=а*sin

Program Pr1; uses crt,graphABC; var y,x,a,b: real; Beginclrscr; setwindowsize (400,400); line (0,200,400,200); line (200,0,200,400); setbrushcolor (clblack); a: =3,2; b: =2; x: =-30; while x <= 30 do begin y: =- (a*sin (x+b)+x); circle (trunc (x*20+200) ,trunc (y*20+200) ,3); x: =x+0,1; end; end.