Нарисовать график функции

Program Tier_LAB;
uses graph;
const
s=0.001;
xs=30;
ys=-30;
var
j,X0,Y0,x,y,a,b:integer;
i:real;
st:string;
 
function f1(x:real):real;
begin
f1:=cos(x);
end;
 
procedure labels;
begin
setcolor(white);
settextstyle(1,0,1);
outtextxy(x0-30,3,'y');
outtextxy(x0+290,y0-35,'x');
line(x0,1,x0,getmaxy);
line(1,y0,getmaxx,y0);
settextstyle(2,0,2);
for j:=-10 to 10 do
begin
setcolor(15);
line(x0+xs*j,y0-7,x0+xs*j,y0+7);
line(x0-7,y0+ys*j,x0+7,y0+ys*j);
setcolor(7);
str(j,st);
outtextxy(x0+xs*j-10,y0+7,st);
if j<>0 then
outtextxy(x0+10,y0+ys*j-10,st);
end;
end;
 
procedure drawgrafik1;
begin
i:=-10;
settextstyle(1,0,4);
repeat
i:=i+s;
x:=round(x0+i*xs);
y:=y0+round(f1(i)*ys);
putpixel(x,y,red);
until i>25;
begin
settextstyle(1,0,1);
setcolor(red);
outtextxy(x0+530,y+10,'y1=2*sin(x-1.4)');
end;
end;
 
 
BEGIN
a:=detect;
initgraph(a,b,'c:\tp\BGI');
x0:=round(getmaxx/2);
y0:=round(getmaxy/2);
labels;
drawgrafik1;
readln;
closegraph;
END.