第十三周实验报告2修改版

 


#include <iostream>

#include<Cmath>  //为便于对比结果，main函数中调用了Cmath中的库函数sin和cos

using namespace std;

const double pi=3.1415926;

double mysin(double);

double mycos(double);

double myabs(double);   //程序中需要求精度的绝对值，也用自定义函数完成吧

int main( )

{

    cout << "sin(π/2)的值为" << mysin(pi / 2) <<endl;

    cout << "cos(87°)的值为" << mycos((87.0 / 180) * pi) <<endl;

    cout << "sin(π/2)的更精确的值为" <<sin(pi / 2) << endl;  //库函数提供的值

    cout << "cos(87°)的更精确的值为" << cos((87.0 / 180) * pi) << endl;

    return 0;

}

double mysin(double x)

{

    double mysin = 0;

    int n = 0, i, fact;

    do

    {

        for(i = 1, fact = 1; i <= 2 * n + 1; i++)

        {

            fact = fact * i;

        }

        mysin = mysin + pow(-1, n) * pow(x, 2 * n + 1) / fact;

        n = n + 1;

    }while(pow(x, 2 * n + 1) / fact > 0.00001);

    return mysin;

}

double mycos(double y)

{ 

    double mycos = 1;

    int n = 1, i, fact = 1;

    do

    {

        for(i = 2, fact = 1; i <= 2 * n; i++)

        {

            fact = fact * i;

        }

        mycos = mycos + pow(-1, n) * pow(y, 2 * n) / fact;

        n = n + 1;

    }while(pow(y, 2 * n) / fact > 0.00001);

    return mycos;

}

 

运行结果：






#include <iostream>

#include<Cmath>  //为便于对比结果，main函数中调用了Cmath中的库函数sin和cos

using namespace std;

const double pi=3.1415926;

double mysin(double);

double mycos(double);

double myabs(double);   //程序中需要求精度的绝对值，也用自定义函数完成吧

int main( )

{

    cout << "sin(π/3)的值为" << mysin(pi / 3) << endl;

    cout << "cos(88°)的值为" << mycos((88.0 / 180) * pi) << endl;

    cout << "sin(π/3)的更精确的值为" <<sin(pi / 3) << endl;  //库函数提供的值

    cout << "cos(88°)的更精确的值为" << cos((88.0 / 180) * pi) <<endl;

  

    return 0;

}

double mysin(double x)

{

    double mysin = 0;

    int n = 0, i, fact;

    do

    {

        for(i = 1, fact = 1; i <= 2 * n + 1; i++)

        {

            fact = fact * i;

        }

        mysin = mysin + pow(-1, n) * pow(x, 2 * n + 1) / fact;

        n = n + 1;

     }while(pow(x, 2 * n + 1) / fact > 0.00001);

   

     return mysin;

}

double mycos(double y)

{ 

    double mycos = 1;

    int n=1, i, fact = 1;

    do

    {

        for(i = 2,fact = 1;i <= 2 * n; i++)

        {

            fact = fact * i;

        }

        mycos = mycos + pow(-1, n) * pow(y, 2 * n) / fact;

        n = n +1 ;

     }while(pow(y, 2 * n) / fact > 0.00001);

   

     return mycos;

}

 




修改感言：

唉~实在是弟子学艺不精啊，可笑还因为得出结果欣喜，结果还是有不足的地方，只是麻烦老师大人，还费心给我指出了，THANK YOU TEACHER，看来计算机也会糊弄人，结果不是一切啊！！！！！！应证了那句话，结果不是那么重要，过程才最important，因为结果有时是假象，呜呜~~~~~~