If F = 0 Then R = (1 - k) ^ (1 / n): GoTo 30
R1 = 0: R2 = 1 ';根在这个范围
GoTo 10
20: If y < 0 Then R1 = R: GoTo 10
If y > 0 Then R2 = R: GoTo 10
10: R = (R1 + R2) / 2
y = R ^ n - (1 - k)
Z = 1
J = 1
For i = 1 To F
J = J * i
Z = Z * (n - i + 1)
y = y + Z / J * R ^ (n - i) * (1 - R) ^ i
Next i
If Abs(y) > 0.00000001 Then GoTo 20
30: Print "R = "; Format(R, "0.0000000")
End Sub