Decimal mathematics operations and decimal array

1. Decimal mathematics operations and decimal array [closed]
2. private void izracunaj_Click(object sender, EventArgs e)
3.     {
4.         double Num;
5.         string masa_voz = masa_vozila_otp_usp.Text.Trim();
6.         bool masa_vozisnum = double.TryParse(masa_voz, out Num);
7.         if (masa_vozisnum)
8.         {
9.             double m = double.Parse(masa_vozila_otp_usp.Text);
10.             double[] P = { 4, 8, 12, 16, 20, 24, 28, 32 };
11.             double[] a = { Math.Atan(P[0] / 100), Math.Atan(P[1] / 100), Math.Atan(P[2] / 100), Math.Atan(P[3] / 100), Math.Atan(P[4] / 100), Math.Atan(P[5] / 100), Math.Atan(P[6] / 100), Math.Atan(P[7] / 100), };
12.             double[] sina = { Math.Sin(a[0]), Math.Sin(a[1]), Math.Sin(a[2]), Math.Sin(a[3]), Math.Sin(a[4]), Math.Sin(a[5]), Math.Sin(a[6]), Math.Sin(a[7]) };
13.             double G = m * 9.81;
14.             double[] Ra = { G * sina[0], G * sina[1], G * sina[2], G * sina[3], G * sina[4], G * sina[5], G * sina[6], G * sina[7] };
15.  
16.             otp_uspona_tbl.Rows.Add(new Object[] { "sin a", sina[0].ToString(), sina[1].ToString(), sina[2].ToString(), sina[3].ToString(), sina[4].ToString(), sina[5].ToString(), sina[6].ToString(), sina[7].ToString() });
17.             otp_uspona_tbl.Rows.Add(new Object[] { "Ra", Ra[0].ToString(), Ra[1].ToString(), Ra[2].ToString(), Ra[3].ToString(), Ra[4].ToString(), Ra[5].ToString(), Ra[6].ToString(), Ra[7].ToString() });
18.         }
19.         else
20.         {
21.             MessageBox.Show("Vrednost u poljima mora biti brojna vrednost", "Greska");
22.         }
23.  
24.     }