泰勒公式求sin（x）感觉没问题啊，但是为什么得不出正确结果

Question

截屏2022-09-14 22.37.23 (2).png

#include <iostream>
#include <cmath>
using namespace std;
double m_sin(double x)
{
    double T,sum = 0;
    double t = x;
    int n = 1;
    long v = 1e-6;
    do
    {
        sum = sum + t;//累加
        n++;//迭代
        t = -t * x * x/(2 * n-1)/(2 * n - 2);//每次乘x^2，变号

    }while (fabs(t)>=v);//循环结束条件
    return sum;//返回m_sin(x)的值
}
int main()
{
    double seita;
    cout<<"请输入角度值(0-360):"<<endl;
    cin>>seita;
    cout<<"sin("<<seita<<")"<<"的值是："<<m_sin(seita)<<endl;
    return 0;
}

Answer 1

double fz = x;
long long fm = 1;
double item = fz/fm;
double sinx= 0;
int flag = 1;
int n = 1;
do
{
     sinx += item*flag;
     fz *= x*x;
     fm *= (n+1)*(n+2);
     item = fz/fm;
     flag = -flag;
     n+=2;
}while(item >= 1e-6);