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59 lines
1.9 KiB
C++

5 years ago
/*----------------- TRAPEZOIDAL RULE OF INTEGRATION -------------------*/
/* THIS PROGRAM CALCULATES THE VALUE OF INTEGRATION USING
TRAPEZIODAL RULE. THE FUNCTION TO BE INTEGRATED IS,
f(x) = 1/x
INPUTS : 1) Lower and upper limits of integration.
2) Number of intervals.
OUTPUTS : Result of integration. */
/*------------------------------ PROGRAM --------------------------*/
#include<stdio.h>
#include<math.h>
#include<stdlib.h>
#include<conio.h>
void main()
{
double fx (double x0);
double lo,up,f[20],h,x0,sum,result;
int i,n;
clrscr();
printf("\n\t TRAPEZOIDAL RULE OF INTEGRATION");
printf("\n\nEnter the lower limit of integration = ");
scanf("%lf",&lo); /* ENTER LOWER LIMIT OF INTEGRATION */
printf("\n\nEnter the upper limit of integration = ");
scanf("%lf",&up); /* ENTER UPPER LIMIT OF INTEGRATION */
printf("\n\nEnter the value of h = ");
scanf("%lf",&h); /* ENTER THE VALUE OF h */
n = (up - lo)/h; /* CALCULATION VALUE OF n */
x0 = lo;
for(i = 0; i <= n; i++) /* LOOP TO CALCULATE VALUE OF f(x) */
{
f[i] = fx(x0); /* FUNCTION fx IS CALLED HERE */
x0 = x0 + h; /* NEXT VALUE OF x IS CALCULATED HERE */
}
sum = 0;
for(i = 1; i <= n-1; i++)
{
sum = sum + 2*f[i]; /*SUMMATION OF ORDINATES FROM y(1) to y(n-1)*/
}
result = (h/2) * ( f[0] + f[n] + sum ); /* RESULT OF INTEGRATION */
printf("\n\nThe result of integration is = %lf",result);
}
double fx ( double x) /* FUNCTION TO CALCULATE VALUE OF f(x) */
{
double f;
f = 1/x;
return(f);
}
/*------------------------ END OF PROGRAM ------------------------------*/