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Numerical Methods Continuous Fourier Series Part: Continuous Fourier Series

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Presentation on theme: "Numerical Methods Continuous Fourier Series Part: Continuous Fourier Series"— Presentation transcript:

1 Numerical Methods Continuous Fourier Series Part: Continuous Fourier Series http://numericalmethods.eng.usf.edu

2 For more details on this topic  Go to http://numericalmethods.eng.usf.eduhttp://numericalmethods.eng.usf.edu  Click on Keyword  Click on Continuous Fourier Series

3 You are free to Share – to copy, distribute, display and perform the work to Remix – to make derivative works

4 Under the following conditions Attribution — You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). Noncommercial — You may not use this work for commercial purposes. Share Alike — If you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one.

5 http://numericalmethods.eng.usf.edu5 Chapter 11.02: Continuous Fourier Series Lecture # 2 For a function with period “T” continuous Fourier series can be expressed as The “average” function value between the time interval [0,T] is given by (22) (23)

6 http://numericalmethods.eng.usf.edu6 Even and Odd functions are described as (24) (25) Continuous Fourier Series

7 http://numericalmethods.eng.usf.edu7 Derivation of formulas for Integrating both sides with respect to time, one gets The second and third terms on the right hand side of the above equations are both zeros (26)

8 http://numericalmethods.eng.usf.edu8 (27) (28) Derivation of formulas for

9 http://numericalmethods.eng.usf.edu9 Now, if both sides are multiplied by and then integrated (29) Derivation of formulas for

10 http://numericalmethods.eng.usf.edu10 The first and second terms on the RHS of Equation (29) are zero. The third RHS term of Equation (29) is also zero, with the exception when (30) Derivation of formulas for

11 http://numericalmethods.eng.usf.edu11 Similar derivation can be used to obtain Derivation of formulas for

12 THE END http://numericalmethods.eng.usf.edu

13 This instructional power point brought to you by Numerical Methods for STEM undergraduate http://numericalmethods.eng.usf.edu Committed to bringing numerical methods to the undergraduate Acknowledgement

14 For instructional videos on other topics, go to http://numericalmethods.eng.usf.edu/videos/ This material is based upon work supported by the National Science Foundation under Grant # 0717624. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

15 The End - Really

16 Numerical Methods Continuous Fourier Series Part: Example 1 http://numericalmethods.eng.usf.edu

17 For more details on this topic  Go to http://numericalmethods.eng.usf.eduhttp://numericalmethods.eng.usf.edu  Click on Keyword  Click on Continuous Fourier Series

18 You are free to Share – to copy, distribute, display and perform the work to Remix – to make derivative works

19 Under the following conditions Attribution — You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). Noncommercial — You may not use this work for commercial purposes. Share Alike — If you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one.

20 http://numericalmethods.eng.usf.edu20 Chapter 11.02: Example 1 (Contd.) Lecture # 3 Using the continuous Fourier series to approximate the Find the Fourier coefficients and Figure 1: A Periodic Function following periodic function in Fig (1).

21 http://numericalmethods.eng.usf.edu21 Example 1 cont. From Equations (23-25), one obtains :

22 http://numericalmethods.eng.usf.edu22 Example 1 cont.

23 http://numericalmethods.eng.usf.edu23 From this equation, we obtain the Fourier coefficients for = -0.9999986528958207 = -0.4999993232285269 = -0.3333314439509194 = -0.24999804122384547 = -0.19999713794872364 = -0.1666635603759553 = -0.14285324664625462 = -0.12499577981019251 Example 1 cont.

24 http://numericalmethods.eng.usf.edu24 We can now find the values of Example 1 cont. from the following equations,

25 http://numericalmethods.eng.usf.edu25 For the Fourier coefficients can be = -0.6366257003116296 = -5.070352857678721e-6  0 = -0.07074100153210318 = -5.070320092569666e-6  0 = -0.025470225589332522 = -5.070265333302604e-6  0 = -0.012997664818977102 = -5.070188612604695e-6  0 Example 1 cont. computed as

26 http://numericalmethods.eng.usf.edu26 Example 1 conclusion In conclusion, the periodic function f(t) (shown in Figure 1) can be expressed as: where and have already computed For one obtains:

27 http://numericalmethods.eng.usf.edu27

28 THE END http://numericalmethods.eng.usf.edu

29 This instructional power point brought to you by Numerical Methods for STEM undergraduate http://numericalmethods.eng.usf.edu Committed to bringing numerical methods to the undergraduate Acknowledgement

30 For instructional videos on other topics, go to http://numericalmethods.eng.usf.edu/videos/ This material is based upon work supported by the National Science Foundation under Grant # 0717624. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

31 The End - Really

32 Numerical Methods Continuous Fourier Series Part: Complex Form of Fourier Series http://numericalmethods.eng.usf.edu

33 For more details on this topic  Go to http://numericalmethods.eng.usf.eduhttp://numericalmethods.eng.usf.edu  Click on Keyword  Click on Continuous Fourier Series

34 You are free to Share – to copy, distribute, display and perform the work to Remix – to make derivative works

35 Under the following conditions Attribution — You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). Noncommercial — You may not use this work for commercial purposes. Share Alike — If you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one.

36 http://numericalmethods.eng.usf.edu36 Chapter 11.02 :Complex form of Fourier Series (Contd.) Lecture # 4 Using Euler’s identity (31) (32) and

37 http://numericalmethods.eng.usf.edu37 Thus, the Fourier series can be casted in the following form: (33) (34) Complex form of Fourier Series cont.

38 http://numericalmethods.eng.usf.edu38 Define the following constants: Hence: (35) (36) (37) Complex form of Fourier Series cont.

39 http://numericalmethods.eng.usf.edu39 Using the even, odd (38) properties Equation (37) becomes: Complex form of Fourier Series cont.

40 http://numericalmethods.eng.usf.edu40 Complex form of Fourier Series cont. Substituting Equations (35,36, 38) into Equation (34), one gets:

41 http://numericalmethods.eng.usf.edu41 or (39) Complex form of Fourier Series cont.

42 http://numericalmethods.eng.usf.edu42 Complex form of Fourier Series cont. The coefficient can be computed, by substituting or (40) Equations (24, 25) into Equation (36) to obtain:

43 http://numericalmethods.eng.usf.edu43 Substituting Equations (31, 32) into the above equation, one gets: (41) Thus, Equations (39, 41) are the equivalent complex version of Equations (21, 25). Complex form of Fourier Series cont.

44 THE END http://numericalmethods.eng.usf.edu

45 This instructional power point brought to you by Numerical Methods for STEM undergraduate http://numericalmethods.eng.usf.edu Committed to bringing numerical methods to the undergraduate Acknowledgement

46 For instructional videos on other topics, go to http://numericalmethods.eng.usf.edu/videos/ This material is based upon work supported by the National Science Foundation under Grant # 0717624. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

47 The End - Really


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