I have a question about this type of question. Will cos(mpix) will always be 0? and how do we determine it will be 0 and when sin(mpix) part also will be 0? moreover, for the sin(mpix) when we do the integration, why the negative sign is canceled? I did not follow.

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
Question

I have a question about this type of question. Will cos(mpix) will always be 0? and how do we determine it will be 0 and when sin(mpix) part also will be 0? moreover, for the sin(mpix) when we do the integration, why the negative sign is canceled? I did not follow.  

11. f (2) = -x -L <a < L; f(2 + 2L) = f (x)
(> Answer
V Solution
(a) The figure shows the case L = 1.
(b) The Fourier series is of the form
f(e) = + om
().
+ bm sin
COS
where the coefficients are computed form Eqs.(8)-(10). Substituting for f(z) in these equations yields
ao = (1/L) /
(-x) da = 0
and
am =
(-2) cos
dz = 0,
m = 1,2,... (these can be shown by direct integration, or using the fact that
g(x) dr = 0 when g(x) is an odd function). Finally,
1
bm =
1
(-x) sin
dr =
de
CoS
Cos
2L cos ma
L
2L(-1)"
sin
--
since cos ma = (-1)". Substituting these terms in the above Fourier series for f(z) yields the desired answer:
Transcribed Image Text:11. f (2) = -x -L <a < L; f(2 + 2L) = f (x) (> Answer V Solution (a) The figure shows the case L = 1. (b) The Fourier series is of the form f(e) = + om (). + bm sin COS where the coefficients are computed form Eqs.(8)-(10). Substituting for f(z) in these equations yields ao = (1/L) / (-x) da = 0 and am = (-2) cos dz = 0, m = 1,2,... (these can be shown by direct integration, or using the fact that g(x) dr = 0 when g(x) is an odd function). Finally, 1 bm = 1 (-x) sin dr = de CoS Cos 2L cos ma L 2L(-1)" sin -- since cos ma = (-1)". Substituting these terms in the above Fourier series for f(z) yields the desired answer:
Expert Solution
steps

Step by step

Solved in 2 steps with 2 images

Blurred answer
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,