# Write C program to find Exponent Power Series

C ProgrammingProgramming

#### Cyber Security : Go from Zero to Hero

Most Popular

60 Lectures 5.5 hours

#### Master C and Embedded C Programming- Learn as you go

Best Seller

66 Lectures 5.5 hours

#### C Programming from scratch- Master C Programming

Best Seller

60 Lectures 8 hours

### Program :

A program to evaluate the power series

``````
x2   x3            xn
ex = 1 + x + --- + --- + ..... + ----
2!     3!            n!
, 0 < x < 1
``````

It uses if……else to test the accuracy.

The power series contains the recurrence relationship of the type

``````
Tn = Tn-1 (---) for n > 1

T1 = x for n = 1

T0 = 1
``````

If Tn-1 (usually known as previous term) is known, then Tn (known as present term) can be easily found by
multiplying the previous term by x/n. Then

``````
ex = T0 + T1 + T2 + ...... + Tn = sum
``````

#### C Program for Exponent Series :

``````
#include <stdio.h>
#define ACCURACY 0.0001

int main() {
int n, count;
float x, term, sum;

printf("\nEnter value of x :");
scanf("%f", &x);

n = term = sum = count = 1;

while (n <= 100) {
term = term * x / n;
sum = sum + term;
count = count + 1;

if (term < ACCURACY)
n = 999;
else
n = n + 1;
}

printf("\nTerms = %d Sum = %f", count, sum);
return 0;
}
``````

#### Output :

``````
Enter value of x:0
Terms = 2 Sum = 1.000000

Enter value of x:0.1
Terms = 5 Sum = 1.105171

Enter value of x:0.5
Terms = 7 Sum = 1.648720

Enter value of x:0.75
Terms = 8 Sum = 2.116997

Enter value of x:0.99
Terms = 9 Sum = 2.691232

Enter value of x:1
Terms = 9 Sum = 2.718279
``````