巧用函数：精确求余弦函数近似值，误差控制在你手！

```c #include <stdio.h> #include <math.h> double funcos( double e, double x ) { double term = 1; double sum = 1; int n = 1; int flag = -1; while (fabs(term) >= e) { double factorial = 1; for (int i = 1; i <= 2 * n; i++) { factorial *= i; } term = flag * pow(x, 2 * n) / factorial; sum += term; flag = -flag; n++; } return sum; } ``` ######[AI问答 | 157点数解答 | 2025-12-10 22:37:05]