Solved

Area under a curve

Posted on 1997-08-05
3
499 Views
Last Modified: 2008-02-26
Area of a region under the curve can be described by taking the integral of the function, given the limits of the curve. My problem is to write a program in C, using "Functions" to calculate the area of the region under the curve. The formula/equation to be used to solve is:
Area=Delta*[ {f(a)/2} + {f(a+delta)} + {f(a+2*delta)} + {f(a+3*delta)} + ............. + {f(a+(n-1)*delta)} + {f(b)/2} ] , where delta=((b-a)/n), a=(-1.0) and b=(1.0) and are REAL.
The equation of the curved line is given by:
y = e^ ((-x^2)/2)

Your quick response will be greatly appreciated. Thank you very much.

Sincerely,
Abdul
<batla@msn.com>
<batla@hotmail.com>
0
Comment
Question by:batla
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
3 Comments
 

Accepted Solution

by:
tomii earned 100 total points
ID: 1252876
I'm assuming that n is the number of points along the curve to take, or in other word, delta = 1-(-1)/n = 2/n....  I'm also assuming that Y=f(x)...  In this case, something like this may work...  (I haven't tested this, so there may be a bug or two)

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

double f(double);
double Area(int, double, double);

void main()
{
      int num_points = 100;

      printf("Area under the curve is: %lf", Area(num_points. -1.0, 1.0));
}
      

double f(double x)
{
      return(exp((-pow(x,2))/2.0));
}

double Area(int n, double start, double end)
{
      double area = 0.0;
      double delta = 0.0;
      long int count = 0;

      delta = (end - start) / n;

      area = f(start) / 2.0;
      area += f(end) / 2.0;

      for(i=start+delta ; i<end ; i+=delta)
      {
            count++;
            area += f(start + (count * delta));
      }

      return(area);
}
      
0
 

Author Comment

by:batla
ID: 1252877
Thanks Tomii. It was a good try but for some reason, it did not work at all. I fixed all the bugs and made it bug-free but it never returned any values to the main and as a result: there was not output. It seemed that it was stuck in some loop. You might wanna try to run it and if runs, e-mail me again. Thanks again for your efforts.

Abdul

0
 

Expert Comment

by:tomii
ID: 1252878
There were some bugs...  It has been mailed to you personally, to batla@msn.com
0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

An Outlet in Cocoa is a persistent reference to a GUI control; it connects a property (a variable) to a control.  For example, it is common to create an Outlet for the text field GUI control and change the text that appears in this field via that Ou…
Examines three attack vectors, specifically, the different types of malware used in malicious attacks, web application attacks, and finally, network based attacks.  Concludes by examining the means of securing and protecting critical systems and inf…
The goal of this video is to provide viewers with basic examples to understand opening and writing to files in the C programming language.
Video by: Grant
The goal of this video is to provide viewers with basic examples to understand and use nested-loops in the C programming language.

690 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question