C Exercises: Calculate the sum of the series [ 1-X^2/2!+X^4/4!- .........]

C For Loop: Exercise-18 with Solution

Write a program in C to find the sum of the series [ 1-X^2/2!+X^4/4!- .........].

Sample Solution:

C Code:

#include <stdio.h>
void main()
{
	float x,sum,t,d;
	int i,n;
	printf("Input the Value of x :");
	scanf("%f",&x);
	printf("Input the number of terms : ");
	scanf("%d",&n);
	sum =1; t = 1;
	for (i=1;i<n;i++)
	{
	  d = (2*i)*(2*i-1);
	  t = -t*x*x/d;
	  sum =sum+ t;
	}
	printf("\nthe sum = %f\nNumber of terms = %d\nvalue of x = %f\n",sum,n,x);
} 

Flowchart:

or

#include <stdio.h>

void main()
{
	float x,s,t,num=1.00,fac=1.00;
	int i,n,pr,y=2,m=1;

	printf("Input the Value of x :");
	scanf("%f",&x);
	printf("Input the number of terms : ");
	scanf("%d",&n);
	s=1.00; t=1.00;

	for (i=1;i<n;i++)
	{
            for(pr=1;pr<=y;pr++)
                 {
                   fac=fac*pr;
                   num=num*x;

                 }   
          m=m*(-1);
          num=num*m;
          t=num/fac;
	  s=s+t;
          y=y+2;
          num=1.00; 
          fac=1.00;
          
	}
	printf("\nthe sum = %f\nNumber of terms = %d\nvalue of x = %f\n",s,n,x);
} 

Sample Output:

Input the Value of x :2                                                                                       
Input the number of terms : 5                                                                                 
                                                                                                              
the sum = -0.415873                                                                                           
Number of terms = 5                                                                                           
value of x = 2.000000  

Flowchart:

C Programming Code Editor:

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