private void btnfig_Click(object sender, EventArgs e)
{
int a = 1;
int b = 0;
int c = 0;
double x, y;
int orig_x = pn1.Width / 2;
int orig_y = pn1.Height / 2;
//
Bitmap pen = new Bitmap(1, 1);
pen.SetPixel(0, 0, Color.Green);
System.Drawing.Graphics g = pn1.CreateGraphics();
//
for (double i = 0; i <= 100; i += 0.01)
{
x = i;
y = (a * (x * x)) + ((b * x) + c);
g.DrawImageUnscaled(pen, orig_x + (int)x, orig_y - (int)y);
g.DrawImageUnscaled(pen, orig_x - (int )x, orig_y - (int)y);
if (y >= orig_y)
{
break;
}
}
}