14.16: Sección 12.3 Respuestas
- Page ID
- 115389
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)1. \(\displaystyle u(x,y)=\frac{8}{\pi ^{3}}\sum_{n=1}^{\infty}\frac{\sinh\left( (2n-1)\pi (1-y)\right)}{(2n-1)^{3}\sinh\left( (2n-1)\pi\right) }\sin (2n-1)\pi x\)
2. \(\displaystyle u(x,y)=-\frac{32}{\pi ^{3}}\sum_{n=1}^{\infty}\frac{(1+(-1)^{n}2)\sinh \left(n\pi (3-y)/2\right)}{n^{3}\sinh\left(3n\pi /2\right)}\sin \frac{n\pi x}{2}\)
3. \(\displaystyle u(x,y)=\frac{8}{\pi ^{2}} \sum_{n=1}^{\infty}(-1)^{n+1}\frac{\sinh \left( (2n-1)\pi (1-y/2)\right)}{(2n-1)^{2}\sinh \left((2n-1)\pi\right)}\sin\frac{(2n-1)\pi x}{2}\)
4. \(\displaystyle u(x,y)=\frac{\pi }{2}\frac{\sinh (1-y)}{\sinh 1}\sin x-\frac{16}{\pi } \sum_{n=1}^{\infty}\frac{n\sinh \left(2n(1-y)\right)}{(4n^{2}-1)^{2}\sinh \left(2n\right)}\sin 2nx\)
5. \(\displaystyle u(x,y)=3y+\frac{108}{\pi ^{3}} \sum_{n=1}^{\infty}(-1)^{n}\frac{\sinh \left(n\pi y/3\right)}{n^{3}\cosh \left(2n\pi /3\right)}\cos\frac{n\pi x}{3}\)
6. \(\displaystyle u(x,y)=\frac{y}{2}+\frac{4}{\pi ^{3}} \sum_{n=1}^{\infty}\frac{\sinh \left((2n-1)\pi y\right)}{(2n-1)^{3}\cosh \left(2(2n-1)\pi\right) }\cos (2n-1)\pi x\)
7. \(\displaystyle u(x,y)=-\frac{8y}{3}+\frac{32}{\pi ^{3}} \sum_{n=1}^{\infty}(-1)^{n}\frac{\sinh \left(n\pi y/2\right)}{n^{3}\cosh \left(n\pi\right) }\cos\frac{n\pi x}{2}\)
8. \(\displaystyle u(x,y)=\frac{y}{3}+\frac{4}{\pi ^{3}} \sum_{n=1}^{\infty}\frac{\sinh \left(n\pi y\right)}{n^{3}\cosh \left(n\pi\right) }\cos n\pi x\)
9. \(\displaystyle u(x,y)=\frac{128}{\pi ^{3}} \sum_{n=1}^{\infty}\frac{\cosh \left((2n-1)\pi (x-3)/4\right)}{(2n-1)^{3}\cosh \left( 3(2n-1)\pi /4\right)}\sin\frac{(2n-1)\pi y}{4}\)
10. \(\displaystyle u(x,y)=-\frac{96}{\pi ^{3}} \sum_{n=1}^{\infty}\left[ 1+(-1)^{n}\frac{4}{(2n-1)\pi }\right]\frac{\cosh \left((2n-1)\pi (x-2)/2\right)}{(2n-1)^{3}\cosh \left((2n-1)\pi\right) }\sin\frac{(2n-1)\pi y}{2}\)
11. \(\displaystyle u(x,y)=\frac{768}{\pi ^{3}} \sum_{n=1}^{\infty}\left[ 1+(-1)^{n}\frac{2}{(2n-1)\pi }\right]\frac{\cosh (2n-1)\pi (x-2)/4}{(2n-1)^{3}\cosh (2n-1)\pi /2}\sin\frac{(2n-1)\pi y}{4}\)
12. \(\displaystyle u(x,y)=\frac{96}{\pi ^{3}} \sum_{n=1}^{\infty}\left[ 3+(-1)^{n}\frac{4}{(2n-1)\pi }\right]\frac{\cosh 3(2n-1)\pi (x-2)/2}{(2n-1)^{3}\cosh (2n-1)\pi /2}\sin\frac{(2n-1)\pi y}{2}\)
13. \(\displaystyle u(x,y)=-\frac{16}{\pi }\sum_{n=1}^{\infty}\frac{\cosh (2n-1)x/2}{(2n-3)(2n+1)(2n-1)\sinh (2n-1)/2}\cos \frac{(2n-1)y}{2}\)
14. \(\displaystyle u(x,y)=-\frac{432}{\pi ^{3}}\sum_{n=1}^{\infty}\left[ 1+\frac{4(-1)^{n}}{(2n-1)\pi }\right] \frac{\cosh (2n-1)\pi x/6}{(2n-1)^{3}\sinh (2n-1)\pi /3}\cos\frac{(2n-1)\pi y}{6}\)
15. \(\displaystyle u(x,y)=-\frac{64}{\pi }\sum_{n=1}^{\infty}(-1)^{n}\frac{\cosh (2n-1)x/2}{(2n-1)^{4}\sinh (2n-1)/2}\cos\frac{(2n-1)y}{2}\)
16. \(\displaystyle u(x,y)=-\frac{192}{\pi ^{4}}\sum_{n=1}^{\infty}\frac{\cosh (2n-1)\pi x/2}{(2n-1)^{4}\sinh (2n-1)\pi /2}\left[(-1)^{n}+\frac{2}{(2n-1)\pi }\right]\cos\frac{(2n-1)\pi y}{2}\)
17. \(\displaystyle u(x,y)= \sum_{n=1}^{\infty}\alpha_{n}\frac{\sinh n\pi y/a}{\sinh n\pi b/a}\sin\frac{n\pi x}{a}\),\(\quad\)\(\displaystyle \alpha_{n}=\frac{2}{a}\int_{0}^{a}f(x)\sin\frac{n\pi x}{a}dx\),\(\quad\)\(\displaystyle u(x,y)=\frac{72}{\pi ^{3}} \sum_{n=1}^{\infty}\frac{\sinh (2n-1)\pi y/3}{(2n-1)^{3}\sinh 2(2n-1)\pi /3}\sin\frac{(2n-1)\pi x}{3}\)
18. \(\displaystyle u(x,y)=\alpha_{0}(1-y/b)+ \sum_{n=1}^{\infty}\alpha_{n}\frac{\sinh n\pi (b-y)/a}{\sinh n\pi b/a}\cos\frac{n\pi x}{a}\),\(\quad\)\(\displaystyle \alpha_{0}=\frac{1}{a}\int_{0}^{a}f(x)dx\),\(\quad\)\(\displaystyle \alpha_{n}=\frac{2}{a}\int_{0}^{a}f(x)\cos\frac{n\pi x}{a}dx,\ n\geq 1\),\(\quad\)\(\displaystyle u(x,y)=\frac{8(1-y)}{15}-\frac{48}{\pi ^{4}} \sum_{n=1}^{\infty}\frac{\sinh n\pi (1-y)}{\sinh n\pi }\cos n\pi x\)
19. \(\displaystyle u(x,y)= \sum_{n=1}^{\infty}\alpha_{n}\frac{\sinh (2n-1)\pi (b-y)/2a}{\sinh (2n-1)\pi b/a}\cos\frac{(2n-1)\pi x}{2a}\),\(\quad\)\(\displaystyle \alpha_{n}=\frac{2}{a}\int_{0}^{a}f(x)\cos\frac{(2n-1)\pi x}{2a}dx\),\(\quad\)\(\displaystyle u(x,y)=\frac{288}{\pi ^{3}} \sum_{n=1}^{\infty}\frac{\sinh (2n-1)\pi (2-y)/6}{(2n-1)^{3}\sinh (2n-1)\pi /3}\sin\frac{(2n-1)\pi x}{6}\)
20. \(\displaystyle u(x,y)= \sum_{n=1}^{\infty}\alpha_{n}\frac{\sinh (2n-1)\pi (b-y)/2a}{\sinh (2n-1)\pi b/2a}\sin\frac{(2n-1)\pi x}{2a}\),\(\quad\)\(\displaystyle \alpha_{n}=\frac{2}{a}\int_{0}^{a}f(x)\sin\frac{(2n-1)\pi x}{2a}dx\),\(\quad\)\(\displaystyle u(x,y)=\frac{32}{\pi ^{3}} \sum_{n=1}^{\infty}\left[ (-1)^{n}5+\frac{18}{(2n-1)\pi }\right]\frac{\sinh (2n-1)\pi (2-y)/2}{(2n-1)^{3}\sinh (2n-1)\pi }\cos\frac{(2n-1)\pi x}{2}\)
21. \(\displaystyle u(x,y)= \sum_{n=1}^{\infty}\alpha_{n}\frac{\cosh n\pi (y-b)/a}{\cosh n\pi b/a}\sin\frac{n\pi x}{a}\),\(\quad\)\(\displaystyle \alpha_{n}=\frac{2}{a}\int_{0}^{a}f(x)\sin\frac{n\pi x}{a}dx\),\(\quad\)\(\displaystyle u(x,y)=-12 \sum_{n=1}^{\infty}(-1)^{n}\frac{\cosh n(y-2)}{n^{3}\cosh 2n}\sin nx\)
22. \(\displaystyle u(x,y)=\alpha_{0}+ \sum_{n=1}^{\infty}\alpha_{n}\frac{\cosh n\pi y/a}{\cosh n\pi b/a}\cos\frac{n\pi x}{a}\),\(\quad\)\(\displaystyle \alpha_{0}=\frac{1}{a}\int_{0}^{a}f(x)dx\),\(\quad\)\(\displaystyle\alpha_{n}=\frac{2}{a}\int_{0}^{a}f(x)\cos\frac{n\pi x}{a}dx,\ n\geq 1\),\(\quad\)\(\displaystyle u(x,y)=\frac{\pi ^{4}}{30}-3 \sum_{n=1}^{\infty}\frac{1}{n^{4}}\frac{\cosh 2ny}{\cos 2n}\cos 2nx\)
23. \(\displaystyle u(x,y)=\frac{a}{\pi } \sum_{n=1}^{\infty}\alpha_{n}\frac{\sinh n\pi (y-b)/a}{n\cosh n\pi b/a}\sin\frac{n\pi x}{a}\),\(\quad\)\(\displaystyle \alpha_{n}=\frac{2}{a}\int_{0}^{a}f(x)\sin\frac{n\pi x}{a}dx\),\(\quad\)\(\displaystyle u(x,y)=\frac{4}{\pi } \sum_{n=1}^{\infty}(-1)^{n+1}\frac{\sinh (2n-1)(y-1)}{(2n-1)^{3}\cosh (2n-1)}\sin (2n-1)x\)
24. \(\displaystyle u(x,y)= \sum_{n=1}^{\infty}\alpha _{n}\frac{\cosh n\pi x/b}{\cosh n\pi a/b}\sin\frac{n\pi y}{b}\),\(\quad\)\(\displaystyle \alpha_{n}=\frac{2}{b}\int_{0}^{b}g(y)\sin\frac{n\pi y}{b}dy\),\(\quad\)\(\displaystyle u(x,y)=\frac{96}{\pi ^{5}} \sum_{n=1}^{\infty}\frac{\cosh (2n-1)\pi x}{(2n-1)^{5}\cosh (2n-1)\pi }\sin (2n-1)\pi y\)
25. \(\displaystyle u(x,y)= \sum_{n=1}^{\infty}\alpha_{n}\frac{\cosh (2n-1)\pi x/2b}{\cosh (2n-1)\pi a/2b}\cos\frac{(2n-1)\pi y}{2b}\),\(\quad\)\(\displaystyle\alpha_{n}=\frac{2}{b}\int_{0}^{b}g(y)\cos\frac{(2n-1)\pi y}{2b}dy\),\(\quad\)\(\displaystyle u(x,y)=-\frac{128}{\pi ^{3}} \sum_{n=1}^{\infty}(-1)^{n}\frac{\cosh (2n-1)\pi x/4}{(2n-1)^{3}\cosh (2n-1)\pi /2}\cos\frac{(2n-1)\pi y}{4}\)
26. \(\displaystyle u(x,y)=\frac{b}{\pi } \sum_{n=1}^{\infty}\alpha_{n}\frac{\cosh n\pi x/b}{n\sinh n\pi a/b}\sin\frac{n\pi y}{b}\),\(\quad\)\(\displaystyle \alpha_{n}=\frac{2}{b}\int_{0}^{b}g(y)\sin\frac{n\pi y}{b}dy\),\(\quad\)\(\displaystyle u(x,y)=\frac{64}{\pi ^{3}} \sum_{n=1}^{\infty}(-1)^{n+1}\frac{\cosh (2n-1)\pi x/4}{(2n-1)^{3}\sinh (2n-1)\pi /4}\sin\frac{(2n-1)\pi y}{4}\)
27. \(\displaystyle u(x,y)=-\frac{2b}{\pi } \sum_{n=1}^{\infty}\alpha_{n}\frac{\cosh (2n-1)\pi (x-a)/2b}{(2n-1)\sinh (2n-1)\pi a/2b}\sin\frac{(2n-1)y}{2b}\),\(\quad\)\(\displaystyle \alpha_{n}=\frac{2}{b}\int_{0}^{b}g(y)\sin\frac{(2n-1)\pi y}{2b}dy\),\(\quad\)\(\displaystyle u(x,y)=192 \sum_{n=1}^{\infty}\left[1+(-1)^{n}\frac{4}{(2n-1)\pi}\right]\frac{\cosh (2n-1)(x-1)/2}{(2n-1)^{4}\sinh (2n-1)/2}\sin\frac{(2n-1)y}{2}\)
28. \(\displaystyle u(x,y)=\alpha_{0}(x-a)+\frac{b}{\pi } \sum_{n=1}^{\infty}\alpha_{n}\frac{\sinh n\pi (x-a)/b}{n\cosh n\pi a/b}\cos\frac{n\pi y}{b}\),\(\quad\)\(\displaystyle \alpha_{0}=\frac{1}{b}\int_{0}^{b}g(y)\cos\frac{n\pi y}{b}dy\),\(\quad\)\(\displaystyle\alpha_{n}=\frac{2}{b}\int_{0}^{b}g(y)\cos\frac{n\pi y}{b}dy\),\(\quad\)\(\displaystyle u(x,y)=\frac{\pi (x-2)}{2}-\frac{4}{\pi } \sum_{n=1}^{\infty}\frac{\sinh (2n-1)(x-2)}{(2n-1)^{3}\cosh 2(2n-1)}\cos (2n-1)y\)
29. \(\displaystyle u(x,y)=\alpha_{0} + \sum_{n=1}^{\infty}\alpha_{n}e^{-n\pi y/a}\cos\frac{n\pi x}{a}\),\(\quad\)\(\displaystyle \alpha_{0}=\frac{1}{a}\int_{0}^{a}f(x)dx\),\(\quad\)\(\displaystyle \alpha_{n}=\frac{2}{a}\int_{0}^{a} f(x)\cos\frac{n\pi x}{a}dx,\ n\geq 1\),\(\quad\)\(\displaystyle u(x,y)=\frac{\pi ^{3}}{2}-\frac{48}{\pi } \sum_{n=1}^{\infty}\frac{1}{(2n-1)^{4}}e^{-(2n-1)y}\cos (2n-1)x\)
30. \(\displaystyle u(x,y)= \sum_{n=1}^{\infty}\alpha_{n}e^{-(2n-1)\pi y/2a}\cos\frac{(2n-1)\pi x}{2a}\),\(\quad\)\(\displaystyle \alpha_{n}=\frac{2}{a}\int_{0}^{a}f(x)\cos\frac{(2n-1)\pi x}{2a}dx\),\(\quad\)\(\displaystyle u(x,y)=-\frac{288}{\pi ^{3}} \sum_{n=1}^{\infty}\frac{(-1)^{n}}{(2n-1)^{3}}e^{-(2n-1)\pi y/6}\cos\frac{(2n-1)\pi x}{6}\)
31. \(\displaystyle u(x,y)= \sum_{n=1}^{\infty}\alpha_{n}e^{-(2n-1)\pi y/2a}\sin\frac{(2n-1)\pi x}{2a}\),\(\quad\)\(\displaystyle \alpha_{n}=\frac{2}{a}\int_{0}^{a}f(x)\sin\frac{(2n-1)\pi x}{2a}dx\),\(\quad\)\(\displaystyle u(x,y)=\frac{32}{\pi } \sum_{n=1}^{\infty}\frac{1}{(2n-1)^{3}}e^{-(2n-1)y/2}\sin\frac{(2n-1)x}{2}\)
32. \(\displaystyle u(x,y)=-\frac{a}{\pi } \sum_{n=1}^{\infty}\frac{\alpha_{n}}{n}e^{-n\pi y/a}\sin\frac{n\pi x}{a}\),\(\quad\)\(\displaystyle\alpha_{n}=\frac{2}{a}\int_{0}^{a}f(x)\sin\frac{n\pi x}{a}dx\),\(\quad\)\(\displaystyle u(x)=4 \sum_{n=1}^{\infty}\frac{(1+(-1)^{n}2)}{n^{4}}e^{-ny}\sin nx\)
33. \(\displaystyle u(x,y)=-\frac{2a}{\pi } \sum_{n=1}^{\infty}\frac{\alpha_{n}}{2n-1}e^{-(2n-1)\pi y/2a}\cos\frac{(2n-1)\pi x}{2a}\),\(\quad\)\(\displaystyle \alpha_{n}=\frac{2}{a}\int_{0}^{a}f(x)\cos\frac{(2n-1)\pi x}{2a}dx\),\(\quad\)\(\displaystyle u(x,y)=\frac{5488}{\pi ^{3}} \sum_{n=1}^{\infty}\frac{1}{(2n-1)^{3}}\left[ 1+\frac{4(-1)^{n}}{(2n-1)\pi }\right]e^{-(2n-1)\pi y/14}\cos\frac{(2n-1)\pi x}{14}\)
34. \(\displaystyle u(x,y)=-\frac{2a}{\pi } \sum_{n=1}^{\infty}\frac{\alpha _{n}}{2n-1}e^{-(2n-1)\pi y/2a}\sin\frac{(2n-1)\pi x}{2a}\),\(\quad\)\(\displaystyle \alpha_{n}=\frac{2}{a}\int_{0}^{a}f(x)\sin\frac{(2n-1)\pi x}{2a}dx\),\(\quad\)\(\displaystyle u(x,y)=-\frac{2000}{\pi ^{3}} \sum_{n=1}^{\infty}\frac{1}{(2n-1)^{3}}\left[(-1)^{n}+\frac{4}{(2n-1)\pi }\right]e^{-(2n-1)\pi y/10}\sin\frac{(2n-1)\pi x}{10}\)
35. \(\displaystyle u(x,y)= \sum_{n=1}^{\infty}\frac{A_{n}\sinh n\pi (b-y)/a+B_{n}\sinh n\pi y/a}{\sinh n\pi b/a}\sin\frac{n\pi x}{a}+ \sum_{n=1}^{\infty}\frac{C_{n}\sinh n\pi (a-x)/b+D_{n}\sinh n\pi x/b}{\sinh n\pi a/b}\sin\frac{n\pi y}{b}\)
36. \(\displaystyle u(x,y)=C+\frac{a}{\pi } \sum_{n=1}^{\infty}\frac{B_{n}\cosh n\pi y/a-A_{n}\cosh n\pi (y-b)/a}{n\sinh n\pi b/a}\cos\frac{n\pi x}{a}+\frac{b}{\pi } \sum_{n=1}^{\infty}\frac{D_{n}\cosh n\pi x/b-C_{n}\cosh n\pi (x-a)/b}{n\sinh n\pi a/b}\cos\frac{n\pi y}{b}\)