$$ \begin{array}{l} \sum_{r=0}^{n} T_{2 r}(x)=\frac{1}{2}\left(1+\frac{1}{\left(1-x^{2}\right)^{1 / 2}} U_{2 n+1}(x)\right) \\ \text { where, } U_{n}(x)=\sin \left(n \cos ^{-1} x\right) \text { and } T_{n}(x)=\cos \left(n \cos ^{-1} x\right) \end{array} $$
5. If \(f(x)=\left\{\begin{array}{cc}0 & -2<x<0 \\ x & 0<x<2\end{array} \quad\right.\)is periodio of period 4 , and whose Fourier series is given by \(\frac{a_{0}}{2}+\sum_{n=1}^{2}\left[a_{n} \cos \left(\frac{n \pi}{2} x\right)+b_{n} \sin \left(\frac{n \pi}{2} x\right)\right], \quad\) find \(a_{n}\)A. \(\frac{2}{n^{2} \pi^{2}}\)B. \(\frac{(-1)^{n}-1}{n^{2} \pi^{2}}\)C. \(\frac{4}{n^{2} \pi^{2}}\)D. \(\frac{2}{n \pi}\)\(\mathbf{E}_{1} \frac{2\left((-1)^{n}-1\right)}{n^{2} \pi^{2}}\)F. \(\frac{4}{n \pi}\)6. Let \(f(x)-2 x-l\) on \([0,2]\). The Fourier sine series for \(f(x)\) is \(\sum_{w}^{n} b_{n} \sin \left(\frac{n \pi}{2} x\right)\), What is \(b, ?\)A. \(\frac{4}{3 \pi}\)B. \(\frac{2}{\pi}\)C. \(\frac{4}{\pi}\)D. \(\frac{-4}{3 \pi}\)E. \(\frac{-2}{\pi}\)F. \(\frac{-4}{\pi}\)7. Let \(f(x)\) be periodic...
Let \(f(x)= \begin{cases}0 & \text { for } 0 \leq x<2 \\ -(4-x) & \text { for } 2 \leq x \leq 4\end{cases}\)- Compute the Fourier cosine coefficients for \(f(x)\).- \(a_{0}=\)- \(a_{n}=\)- What are the values for the Fourier cosine series \(\frac{a_{0}}{2}+\sum_{n=1}^{\infty} a_{n} \cos \left(\frac{n \pi}{4} x\right)\) at the given points.- \(x=2:\)- \(x=-3\) :- \(x=5:\)
Suppose that \(\left(\xi_{j}\right)^{\infty}=1\) is a sequence of independent identically distributed \((i . i . d .)\) continuous random variables.- Suppose that each \(\xi_{i}\) has a probability density function \(p_{i}(x)=\left\{\begin{array}{c}\frac{\beta}{x^{x}}, x \geq 1 \\ 0, x<1\end{array}\right.\), where \(\alpha, \beta \in\)R.- Let \(S_{n}=\sum_{i=1}^{n} \xi_{i}\).- Let \(S_{n}=\frac{s_{n}-\operatorname{mE}\left(\xi_{0}\right)}{\sqrt{n} \operatorname{Var}(\mathcal{B})}\).a. Find a condition on \(\alpha\) and a condition on \(\beta\) (as a function of \(\alpha\) ) which together make \(f_{1}(x)\) a probability density function.b. Find conditions on \(\alpha\) which guarantee that \(\lim _{n \rightarrow \infty}...
Determine whether the series converges or diverges.(1) \(\sum_{n=1}^{\infty} \frac{e^{1 / n}}{n^{2}}\)(2) \(\sum_{n=1}^{\infty}\left(\frac{2}{\sqrt{n}}+\frac{(-1)^{n}}{3^{n+1}}\right)\)(3) \(\sum_{n=1}^{\infty} \frac{5-2 \sin n}{n}\)(4) \(\sum_{n=1}^{\infty} \frac{3+\cos n}{n^{3 / 2}}\)(5) \(\sum_{n=0}^{\infty} \frac{\sqrt{n^{2}+2}}{n^{4}+n^{2}+5}\)(6) \(\sum_{n=1}^{\infty=1}\left(1+\frac{1}{n}\right)^{n}\)(7) \(\sum_{n=1}^{\infty} \frac{n+1}{n 2^{n}}\)(8) \(\sum_{n=1}^{\infty} \frac{\arctan n}{n^{4}}\)(9) \(\sum_{n=1}^{\infty} n \sin \frac{1}{n}\)
Frequency-domain sampling. Consider the following discrete-time signal$$ x(n)= \begin{cases}a^{|n|}, & |n| \leq L \\ 0, & |n|>L\end{cases} $$where \(a=0.95\) and \(L=10\).(a) Compute and plot the signal \(x(n)\).(b) Show that$$ X(\omega)=\sum_{n=-\infty}^{\infty} x(n) e^{-j \omega n}=x(0)+2 \sum_{n-1}^{L} x(n) \cos \omega n $$Plot \(X(\omega)\) by computing it at \(\omega=\pi k / 100, k=0,1, \ldots, 100\).(c) Compute$$ c_{k}=\frac{1}{N} X\left(\frac{2 \pi}{N} K\right), \quad k=0,1, \ldots, N-1 $$for \(N=30\).(d) Determine and plot the signal$$ \tilde{x}(n)=\sum_{k=0}^{N-1} c k e^{j(2 \pi / N) k n} $$What is the...
Determine whether the series converges, and if so, find its sum. (1) \(\sum_{n=1}^{\infty} 3^{-n} 8^{n+1}\)\((2) \sum_{n=2}^{\infty} \frac{1}{n(n-1)}\)(3) \(\sum_{n=0}^{\infty}(-3)\left(\frac{2}{3}\right)^{2 n}\)(4) \(\sum_{n=1}^{\infty} \frac{1}{e^{2 n}}\)(5) \(\sum_{n=1}^{\infty} \ln \frac{n}{n+1}\)(6) \(\sum_{n=1}^{\infty}[\arctan (n+1)-\arctan n]\)(7) \(\sum_{n=1}^{\infty} \ln \left(\frac{n^{2}+4}{2 n^{2}+1}\right)\)(8) \(\sum_{n=1}^{\infty} \frac{1+2^{n}}{3^{n}}\)(9) \(\sum_{n=1}^{\infty}\left[\cos \frac{1}{n^{2}}-\cos \frac{1}{(n+1)^{2}}\right]\)
Consider the linear system \(A x=b\) where \(A=\left[\begin{array}{rr}2 & -1 \\ -1 & 2\end{array}\right], b=\left[\begin{array}{l}1 \\ 1\end{array}\right], x=\left[\begin{array}{l}1 \\ 1\end{array}\right]\).We showed in class, using the eigenvlaues and eigenvectors of the iteration matrix \(M_{G S}\), that for \(x^{(0)}=\left[\begin{array}{ll}0 & 0\end{array}\right]^{T}\) the error at the \(k^{t h}\) step of the Gauss-Seidel iteration is given by$$ e^{(k)}=\left(\frac{1}{4}\right)^{k}\left[\begin{array}{l} 2 \\ 1 \end{array}\right] $$for \(k \geq 1\). Following the same procedure, derive an analogous expression for the error in Jacobi's method for the same system.
The IVP$$ \begin{array}{c} \sin (t) \frac{d^{2} x}{d t^{2}}+\cos (t) \frac{d x}{d t}+\sin (t) x=\tan (t) \\ x(0.75)=12 \\ \left.\frac{d x}{d t}\right|_{0,75}=2 \end{array} $$has a unique solution defined on the interval
Defining the cross product The cross product of two nonzero vectors \(\vec{u}\) and \(\vec{v}\) is another vector \(\vec{u} \times \vec{v}\) with magnitude$$ |\vec{u} \times \vec{v}|=|\vec{u}||\vec{v}| \sin (\theta), $$where \(0 \leq \theta \leq \pi\) is the angle between the two vectors. The direction of \(\vec{u} \times \vec{v}\) is given by the right hand rule: when you put the vectors tail to tail and let the fingers of your right hand curl from \(\vec{u}\) to \(\vec{v}\) the direction of \(\vec{u} \times \vec{v}\)...
14. Solve the P.D.E.$$ \frac{\partial^{2} u}{\partial x^{2}}+\frac{\partial^{2} u}{\partial y^{2}}=0 ; u(x, 0)=u(0, y)=0, u(x, 1)=\pi, u(1, y)=2 \pi $$$$ \text { 令 } u(x, y)=\phi(x, y)+\varphi(x, y) $$$$ u(x, y)=\sum_{n=1}^{\infty} \frac{2}{n \sinh n \pi}\left[1-(-1)^{n}\right](\sinh n \pi y \sin n \pi x+2 \sinh n \pi x \sin n \pi y) $$