/*

 * C Program to Find the Sum of A.P Series

 */

#include <stdio.h>

#include <math.h>

int main()

{

     int a, d, n, i, tn;

     int sum = 0;

     printf("Enter the first term value of the A.P. series: ");

     scanf("%d", &a);

     printf("Enter the total numbers in the A.P. series: ");

     scanf("%d", &n);

     printf("Enter the common difference of A.P. series: ");

     scanf("%d", &d);

     sum = (n * (2 * a + (n - 1)* d ))/ 2;

     tn = a + (n - 1) * d;

     printf("Sum of the A.P series is: ");

     for (i = a; i <= tn; i = i + d )

     {

          if (i != tn)

               printf("%d + ", i);

          else

               printf("%d = %d ", i, sum);

     }

     return 0;

}

/*

 * C Program to Find the Sum of G.P Series

 */

#include <stdio.h>

#include <math.h>

int main()

{

    float a, r, i, last_term, sum = 0;

    int n;

    printf("Enter the first term of the G.P. series: ");

    scanf("%f", &a);

    printf("Enter the total numbers in the G.P. series: ");

    scanf("%d", &n);

    printf("Enter the common ratio of G.P. series: ");

    scanf("%f", &r);

    sum = (a *(1 - pow(r, n + 1))) / (1 - r);

    last_term = a * pow(r, n - 1);

    printf("last_term term of G.P.: %f", last_term);

    printf("\n Sum of the G.P.: %f", sum);

    return 0;

}

/*

 * C Program to find the sum of series 1^2 + 2^2 + …. + n^2.

 */

#include <stdio.h>

int main()

{

    int number, i;

    int sum = 0;

    printf("Enter maximum values of series number: ");

    scanf("%d", &number);

    sum = (number * (number + 1) * (2 * number + 1 )) / 6;

    printf("Sum of the above given series : ");

    for (i = 1; i <= number; i++)

    {

        if (i != number)

            printf("%d^2 + ", i);

        else

            printf("%d^2 = %d ", i, sum);

    }

    return 0;

}

/*

 * C Program to Find Sum of the Series 1/1! + 2/2! + 3/3! + ……1/N!

 */

#include <stdio.h>

double sumseries(double);

main()

{

    double number,sum;

    printf("\n Enter the value:  ");

    scanf("%lf", &number);

    sum = sumseries(number);

    printf("\n Sum of the above series = %lf ", sum);

}

double sumseries(double m)

{

    double sum2 = 0, f = 1, i;

    for (i = 1; i <= m; i++)

    {

        f = f * i;

        sum2 = sum2 +(i / f);

    }

    return(sum2);

}