Function AINVR(alpha As Double) As Double '定义函数名及输入数据类型'
Dim temp As Double '定义循环初始值数据类型'
temp = 3.1415926 / 2 '赋值循环初始值' Do Until Abs(Tan(temp) - temp - alpha) < 0.0000000001 '设置循环结束条件,数据精度'
temp = temp - (Tan(temp) - temp - alpha) / (Tan(temp) ^ 2) '牛顿法循环求解'
Loop
If alpha <= 0 Then
AINVR = 0
Else
AINVR = temp
End If
End Function