Simpson - PowerPoint PPT Presentation

About This Presentation
Title:

Simpson

Description:

A power point presentation describing Simpson's 1/3rd Rule – PowerPoint PPT presentation

Number of Views:161
Avg rating:3.0/5.0
Slides: 32
Provided by: AutarK85
Category:

less

Transcript and Presenter's Notes

Title: Simpson


1
Simpsons 1/3rd Rule of Integration
  • Civil Engineering Majors
  • Authors Autar Kaw, Charlie Barker
  • http//numericalmethods.eng.usf.edu
  • Transforming Numerical Methods Education for STEM
    Undergraduates

2
Simpsons 1/3rd Rule of Integration
http//numericalmethods.eng.usf.edu
3
What is Integration?
  • Integration

The process of measuring the area under a curve.
Where f(x) is the integrand a lower limit of
integration b upper limit of integration
4
  • Simpsons 1/3rd Rule

5
Basis of Simpsons 1/3rd Rule
  • Trapezoidal rule was based on approximating the
    integrand by a first
  • order polynomial, and then integrating the
    polynomial in the interval of
  • integration. Simpsons 1/3rd rule is an
    extension of Trapezoidal rule
  • where the integrand is approximated by a second
    order polynomial.

Hence
6
Basis of Simpsons 1/3rd Rule
Choose
and
as the three points of the function to evaluate
a0, a1 and a2.
7
Basis of Simpsons 1/3rd Rule
Solving the previous equations for a0, a1 and a2
give
8
Basis of Simpsons 1/3rd Rule
Then
9
Basis of Simpsons 1/3rd Rule
Substituting values of a0, a1, a 2 give
Since for Simpsons 1/3rd Rule, the interval a,
b is broken
into 2 segments, the segment width
10
Basis of Simpsons 1/3rd Rule
11
Example 1


The concentration of benzene at a critical
location is given by
where
So in the above formula
Since decays rapidly as , we
will approximate
  1. Use Simpson 1/3rd rule to find the approximate
    value of erfc(0.6560).
  2. Find the true error, for part (a).
  3. Find the absolute relative true error, for
    part (a).

12
Solution



a)
















13
Solution (cont)

b) The exact value of the above integral cannot
be found. We assume the value obtained by
adaptive numerical integration using Maple as the
exact value for calculating the true error and
relative true error.






True Error

14
Solution (cont)
c) The absolute relative true error,






15
  • Multiple Segment Simpsons 1/3rd Rule

16
Multiple Segment Simpsons 1/3rd Rule
Just like in multiple segment Trapezoidal Rule,
one can subdivide the interval
a, b into n segments and apply Simpsons 1/3rd
Rule repeatedly over
every two segments. Note that n needs to be
even. Divide interval
a, b into equal segments, hence the segment
width
where
17
Multiple Segment Simpsons 1/3rd Rule
Apply Simpsons 1/3rd Rule over each interval,
18
Multiple Segment Simpsons 1/3rd Rule
Since
19
Multiple Segment Simpsons 1/3rd Rule
Then
20
Multiple Segment Simpsons 1/3rd Rule
21
Example 2


The concentration of benzene at a critical
location is given by
where
So in the above formula
Since decays rapidly as ,
we will approximate
  1. Use four segment Simpsons 1/3rd Rule to find the
    approximate value of erfc(0.6560).
  2. Find the true error, for part (a).
  3. Find the absolute relative true error, for
    part (a).

22
Solution


Using n segment Simpsons 1/3rd Rule,
a)



So





23
Solution (cont.)







24
Solution (cont.)
In this case, the true error is
b)




The absolute relative true error
c)
25
Solution (cont.)
Table 1 Values of Simpsons 1/3rd Rule for
Example 2 with multiple segments
Approximate Value
2 4 6 8 10 -0.47178 -0.30529 -0.30678 -0.31110 -0.31248 0.15846 -0.0080347 -0.0065444 -0.0022249 -0.00084868 50.573 2.5643 2.0887 0.71009 0.27086
26
Error in the Multiple Segment Simpsons 1/3rd Rule
The true error in a single application of
Simpsons 1/3rd Rule is given as
In Multiple Segment Simpsons 1/3rd Rule, the
error is the sum of the errors
in each application of Simpsons 1/3rd Rule. The
error in n segment Simpsons
1/3rd Rule is given by
27
Error in the Multiple Segment Simpsons 1/3rd Rule
. . .
28
Error in the Multiple Segment Simpsons 1/3rd Rule
Hence, the total error in Multiple Segment
Simpsons 1/3rd Rule is
29
Error in the Multiple Segment Simpsons 1/3rd Rule
The term
is an approximate average value of
Hence
where
30
Additional Resources
  • For all resources on this topic such as digital
    audiovisual lectures, primers, textbook chapters,
    multiple-choice tests, worksheets in MATLAB,
    MATHEMATICA, MathCad and MAPLE, blogs, related
    physical problems, please visit
  • http//numericalmethods.eng.usf.edu/topics/simpso
    ns_13rd_rule.html

31
  • THE END
  • http//numericalmethods.eng.usf.edu
Write a Comment
User Comments (0)
About PowerShow.com