(25 marks) Solve the following initial value problem using Fourier transform.
$$ \begin{array}{l} u_{t}=u_{x x}, \quad-\infty< x <\infty, t= >0 \\ u(x, 0)=\left(1-2 x^{2}\right) e^{-4 x^{2}}, \quad-\infty< x <\infty \end{array} $$
with \(u(x, t) \rightarrow 0\) and \(u_{x}(x, t) \rightarrow 0\) as \(x \rightarrow \pm \infty\).
10 have requested this problem solution
The more requests, the faster the answer.
(35 marks) The vibration of a semi-infinite string is described by the following initial boundary value problem.(35 marks) The vibration of a semi-infinite string is described by the following initial boundary value problem.$$ \begin{array}{l} u_{t t}=c^{2} u_{x x}, \quad 0< x < \infty, t>0 \\ u(x, 0)=A e^{-\alpha x} \quad \text { and } \quad u_{t}(x, 0)=0, \quad 0< x < \infty \\ u(0, t)=A \cos \omega t, \quad t>0 \\ \lim _{x \rightarrow \infty} u(x, t)=0, \quad \lim _{x...
Solve the following initial boundary value problem using Laplace transform.$$ \begin{aligned} u_{t} &=u_{x x}+t e^{-\pi^{2} t} \sin (\pi x), & 0<x<1, t="">0 \\ u(0, t)=0, & u(1, t)=0, & t>0 & \\ u(x, 0) &=\sin (2 \pi x) & & \end{aligned} $$
Transform the following IBVP into a problem with homogeneous boundary conditions.$$ \begin{array}{l} u_{t t}=u_{x x}, \quad 0<x<1, t=>0 \\ a u(0, t)+b u_{x}(0, t)=f_{1}(t) \quad \text { and } \quad c u(1, t)+d u_{x}(1, t)=f_{2}(t), \quad t>0 \\ u(x, 0)=g(x), \quad u_{t}(x, 0)=h(x), \quad 0<x<1 \end{array} $$where \(a, b, c\) and \(d\) are constants.
Use the Laplace transform to solve the given initial-value problem.$$ y^{\prime}+y=f(t), \quad y(0)=0, \text { where } f(t)=\left\{\begin{array}{rr} 0, & 0 \leq t<1 \\ 5, & t \geq 1 \end{array}\right. $$
use the method of separation of variables to solve the following nonhomogeneous initial-Neumann problem: Hint: write the candidate solution as are the eigenfunctionsof the eigenvalue problem associated with the homogeneous equation.
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...
Solve using the Fourier Transform Method. 2.24) Solve Laplace's equation in a strip using Fourier transforms: u,)+ e-lal, u(x, L) = 0, u(x, y)0 as0o.
Find the solution \(\boldsymbol{u}(\boldsymbol{x}, \boldsymbol{t})\) for the wave problem on a string of length \(\boldsymbol{L}=\pi\) with \(c^{2}=1\) and conditions given by:\(\left\{\begin{array}{l}u(0, t)=0, u(\pi, t)=0, \quad t>0 \\ u(x, 0)=0,\left.\quad \frac{\partial u}{\partial t}\right|_{t=0}=\sin x, 0<x<\pi\end{array}\right.\)
1. Use the Fourier Transform to solve the following problem with W1 21 (a) Find the Fourier Transform of u by applying F to the equation and initial condition; denote this function U(w, t). (b) Find u u(z, t) by taking the inverse transform of the U(w, t) you found in part (a). 1. Use the Fourier Transform to solve the following problem with W1 21 (a) Find the Fourier Transform of u by applying F to the equation and...
( 30 marks) Solve the initial value problem$$ \begin{aligned} \ddot{x} &=-4 x+3 y \\ \ddot{y} &=2 x-3 y \\ x(0)=0, & y(0)=0, & \dot{x}(0)=2, \quad \dot{y}(0)=1 \end{aligned} $$