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C program for sin(x) series

Submitted by Ashish Varshney, on March 19, 2018

What is sin(x) series?

Sin x is a series of sin function of trigonometry; it can expand up to infinite number of term. Through this series, we can find out value of sin x at any radian value of sin x graph.

Reference: The Infinite Series Module.

Formula to Calculate six(x) Series

Here is the formula to calculate six(x) series:

Logic to calculate sin(x) series

1. First the computer reads the value of x and limit from the user.
2. Now convert x to radian value x=x*(3.1415\180)
3. Then using for loop the value of sin(x) is calculated.
4. Finally the value of sin(x) is printed.

Program for sin(x) series in C

#include <stdio.h>
#include <math.h>

int fac(int x) {
  int i, fac = 1;
  for (i = 1; i <= x; i++)
    fac = fac * i;
  return fac;
}

int main() {
  float x, Q, sum = 0;
  int i, j, limit;

  printf("Enter the value of x of sinx series: ");
  scanf("%f", & x);

  printf("Enter the limit upto which you want to expand the series: ");
  scanf("%d", & limit);

  Q = x;
  x = x * (3.1415 / 180);

  for (i = 1, j = 1; i <= limit; i++, j = j + 2) {
    if (i % 2 != 0) {
      sum = sum + pow(x, j) / fac(j);
    } else
      sum = sum - pow(x, j) / fac(j);
  }

  printf("Sin(%0.1f): %f", Q, sum);
  return 0;
}

Output

Enter the value of x of sinx series: 40
Enter the limit upto which you want to expand the series: 5
Sin(40.0): 0.642772

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