已知cosx的幂级数为：cos(x)=1−x22!+x44!−x66!+...+(−1)nx2n(2n)!+...cos(x)=1−x22!+x44!−x66!+...+(−1)nx2n(2n)!+…设计程序用于计算幂级数中的通项(−1)nx2n(2n)!(−1)nx2n(2n)!的值，并计算cosx的值(结果保留4位有效数字)，通项精度不小于0.00001。#include<iostream>#include<math.h>#include<iomanip>int main() { using namespace std; double x,sum=1; static double t=1; cin>>x; for (int i=1;fabs(t)>0.00001;i++) { t*=x*x; t/=2*i*(2*i-1); t*=-1; sum+=t; } cout<<"cos("<<x<<") = "<<fixed<<setprecision(4)<<sum; return 0;}