C# 查找第 N 个根
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C# Find Nth Root
提问by illusion
I use below method to calculate Nth Root of double value, but it takes a lot of time for calculating the 240th root. I found out about Newton method, but was not able to implement it into a method. Any help would be appreciated.
我使用下面的方法来计算 double 值的 Nth Root，但是计算 240th 根需要很多时间。我发现了牛顿法，但无法将其实现为方法。任何帮助，将不胜感激。
static double NthRoot(double A, int N)
{
double epsilon = 0.00001d;//
double n = N;
double x = A / n;
while (Math.Abs(A-Power(x,N)) > epsilon)
{
x = (1.0d/n) * ((n-1)*x + (A/(Power(x, N-1))));
}
return x;
}
采纳答案by Stefan Dragnev
回答by Abhas Bhoi
You can use the same function used to find the power of a number, just use reciprocal of the number instead of the number itself.
您可以使用与用于求数字的幂相同的函数，只需使用数字的倒数而不是数字本身。
To find N root of X you can write,
要找到 X 的 N 个根，你可以这样写，
int root = Convert.ToInt32(Math.Pow(X, (1 / N));
