c - 需要麦克劳林级数和泰勒级数的编程帮助吗？

Question

好的，这是我到目前为止所拥有的:

#include <stdio.h>
#include <math.h>
//#define PI 3.14159

int factorial(int n){
  if(n <= 1)
    return(1);
  else
    return(n * factorial(n-1));
}

void McLaurin(float pi){
  int factorial(int);
  float x = 42*pi/180;
  int i, val=0, sign;

  for(i=1, sign=-1; i<11; i+=2){
    sign *= -1; // alternate sign of cos(0) which is 1
    val += (sign*(pow(x, i)) / factorial(i));
  }

  printf("\nMcLaurin of 42 = %d\n", val);
}

void Taylor(float pi){
  int factorial(int);
  float x;
  int i;
  float val=0.00, sign;
  float a = pi/3;

  printf("Enter x in degrees:\n");
  scanf("%f", &x);
  x=x*pi/180.0;
  printf("%f",x);

  for(i=0, sign=-1.0; i<2; i++){
    if(i%2==1)
      sign *= -1.0; // alternate sign of cos(0) which is 1
    printf("%f",sign);
    if(i%2==1)
      val += (sign*sin(a)*(pow(x-a, i)) / factorial(i));
    else
      val += (sign*cos(a)*(pow(x-a, i)) / factorial(i));
    printf("%d",factorial(i));
  }

  printf("\nTaylor of sin(%g degrees) = %d\n", (x*180.0)/pi, val);
}

main(){
  float pi=3.14159;
  void McLaurin(float);
  void Taylor(float);

  McLaurin(pi);
  Taylor(pi);
}

这是输出:

McLaurin of 42 = 0
Enter x in degrees:
42
0.733038-1.00000011.0000001
Taylor of sin(42 degrees) = -1073741824

我怀疑这些离谱数字的原因与我混淆了浮点数和整数的事实有关？但我就是想不通……!!也许它是一个数学问题，但它从来都不是我的强项，更不用说用微积分编程了。麦克劳林也失败了，它怎么等于零？卧槽!请帮助纠正我的菜鸟代码。我还是初学者。。。

- - 更新 - -

#include <stdio.h>
#include <math.h>
//#define PI 3.14159

int factorial(int n){
  if(n <= 1)
    return(1);
  else
    return(n * factorial(n-1));
}

void McLaurin(float pi){
  int factorial(int);
  float x = 42*pi/180, val=0;
  int i, sign;

  for(i=1, sign=-1; i<11; i+=2){
    sign *= -1; // alternate sign of cos(0) which is 1
    val += (sign*(pow(x, i)) / factorial(i));
  }

  printf("\nMcLaurin of of sin(%f degrees) = %f\n", (x*180.0)/pi, val);
}

void Taylor(float pi){
  int factorial(int);
  float x;
  int i;
  float val=0, sign;
  float a = pi/3;

  printf("Enter x in degrees:\n");
  scanf("%f", &x);
  x=x*pi/180.0;
  printf("%f",x);

  for(i=0, sign=-1.0; i<2; i++){
    if(i%2==0)
      sign *= -1; // alternate sign of cos(0) which is 1
    printf("%f",sign);
    if(i%2==0)
      val += (sign*sin(a)*(pow(x-a, i)) / factorial(i));
    else
      val += (sign*cos(a)*(pow(x-a, i)) / factorial(i));
    printf("%d",factorial(i));
  }

  printf("\nTaylor of sin(%f degrees) = %f\n", (x*180.0)/pi, val);
}

main(){
  float pi=3.14159;
  void McLaurin(float);
  void Taylor(float);

  McLaurin(pi);
  Taylor(pi);
}

给我奇怪的错误。

/usr/lib/gcc/i686-pc-cygwin/3.4.4/../../../../i686-pc-cygwin/bin/ld: cannot open output file a.exe: Device or resource busy
collect2: ld returned 1 exit status
Can anyone explain what's wrong now?

Answer 1

一些潜在的错误来源:

你的 pi 值没有足够的数字来保证浮点精度；

在您的 Maclaurin 函数中，您将 val 作为一个整数，对其进行除法运算；

在 Taylor 中，您只使用系列中的 2 个术语

我认为 ？