C++ Program to calculate the value of sin(x) and cos(x)

Given with the input as angles and the task is to calculate the value of sin(x) and cos(x) corresponding to the given angle and display the result

For Sin(x)

Sin(x) is a trigonometric function which is used to calculate the value of x angle.

Formula

$$\sin (x) = \displaystyle\sum\limits_{k=0}^\infty \frac{(-1)^{k}}{(2k+1)!}x^{2k+1}$$

For Cos(x)

Cos(x) is a trigonometric function which is used to calculate the value of x angle.

Formula

$$\cos (x) = \displaystyle\sum\limits_{k=0}^\infty \frac{(-1)^{k}}{(2k)!}x^{2k}$$

Approach used in the below program is as follows −

• Input the value of x angle for sin(x) and cos(x)
• Apply the formulas given for sin(x) and cos(x)
• Print the result

ALGORITHM

START
Step 1-> declare function to calculate value of sin
   void cal_sin(float n)
   declare and set float acc = 0.0001, denominator, sinx, sinval
   Set n = n * (3.142 / 180.0)
   Declare float temp = n
   Set sinx = n
   Set sinval = sin(n)
   Declare and set int i = 1
   DO
      set denominator = 2 * i * (2 * i + 1)
      set temp = -temp * n * n / denominator
      Set sinx = sinx + temp
      Set i = i + 1
   While(acc <= fabs(sinval - sinx))
      print sinx
Step 2-> Declare function to calculate value of cos
   void cal_cos(float n)
   Declare and set float acc = 0.0001, temp, denominator, cosx, cosval
   Set n = n * (3.142 / 180.0)
   Set temp = 1
   set cosx = temp
   set cosval = cos(n)
   Set int i = 1
   Do
      set denominator = 2 * i * (2 * i - 1)
      Set temp = -temp * n * n / denominator
      Set cosx = cosx + temp
      Set i = i + 1
   While(acc <= fabs(cosval - cosx))
      print cosx
Step 3-> In main()
   Declare float n = 30
   Call cal_sin(n0
   set n=60
   Call cal_cos(n)
STOP

Example

#include <iostream>
#include <math.h>
using namespace std;
//calculate value of sin
void cal_sin(float n) {    
    float acc = 0.0001, denominator, sinx, sinval;
    n = n * (3.142 / 180.0);  //convert in radian
    float temp = n;
    sinx = n;          
    sinval = sin(n);    
    int i = 1;
    do {
        denominator = 2 * i * (2 * i + 1);
        temp = -temp * n * n / denominator;
        sinx = sinx + temp;
        i = i + 1;
    } while (acc <= fabs(sinval - sinx));
    cout<<sinx;
}
//calculate value of cos  
void cal_cos(float n) {
    float acc = 0.0001, temp, denominator, cosx, cosval;
    n = n * (3.142 / 180.0); //convert in radiam
    temp = 1;
    cosx = temp;          
    cosval = cos(n);
    int i = 1;
    do {
        denominator = 2 * i * (2 * i - 1);
        temp = -temp * n * n / denominator;
        cosx = cosx + temp;
        i = i + 1;
    } while (acc <= fabs(cosval - cosx));
    cout<< cosx;
}
int main() {
    float n = 30;
    cout<<"value of Sin is : "; cal_sin(n);
cout<<"\n";
    n=60;
cout<<"value of Cos is : ";
cal_cos(n);
    return 0;
}

Output

value of Sin is : 0.500061
value of Cos is : 0.499847