Private Sub CommandButton1_Click()

x = Sheet1.Cells(1, 2)

Pi = Sheet1.Cells(1, 3)

x = x - Int(x / 2 / Pi) * 2 * Pi

Sum = 1

n = 1

eps = 10 ^ (-10)

Do

Sum = Sum * (1 - x ^ 2 / Pi ^ 2 / n ^ 2)

n = n + 1

Loop Until (x ^ 2 / Pi ^ 2 / n ^ 2 <= eps)

Sheet1.Cells(2, 2) = Sum * x

Sheet1.Cells(2, 3) = n

End Sub