答案 （可通过左边的bookmark迅速查找答案）.docVIP

答案 (可通过左边的bookmark迅速查找答案) 第一次练习 1．在主窗口输入： a=exp(1) A=pi exp(pi)-pi^exp(1) %比较eπ和πe的大小 2．A=rand(3,3) %产生随机数矩阵 B=inv(A) %求A的逆矩阵 C=B*A D=B.*A E=sqrt(C) format short %设置数据的形式 E 第二次练习 1．%%质点运动图形 clear; t=0:0.05:1000; w1=2; w2=[1,2,4,3,5,7,sqrt(3),sqrt(5),exp(1)];%w2可以选不同的值 x=sin(w1*t); for n=1:9; y=sin(w2(n)*t); subplot(3,3,n); plot(x,y); end 2. %%本征函数静态 %画出四种本征函数系sin(nπx/l), cos(nπx/l), sin((n+1/2)πx/l), cos((n+1/2)πx/l)的图形,其中n取1，2，3，4。 clear;clf; n=1:3; x=0:0.01:1; [X N]=meshgrid(x,n) Y1=sin(pi*N.*X); Y2=cos(pi*N.*X); Y3=sin(pi*(N+1/2).*X); Y4=cos(pi*(N+1/2).*X); Y=cat(3,Y1,Y2,Y3,Y4); for k=1:4 subplot(2,2,k) plot(x,Y(:,:,k),b) axis([0,1,-1,1]) end 第三次练习 1. %%本征函数动态 clear;clf;clc; n=1:3;% x=0:0.04:1; t=0:0.02*pi:0.8*pi; [X N T]=meshgrid(x,n,t); for k=1:50 subplot(2,1,1) Y1=sin(pi*N(:,:,1).*X(:,:,1)).*cos(pi*N(:,:,1).*T(:,:,k)); plot(x,Y1); axis([0,1,-1,1]) m1(:,k)=getframe; subplot(2,1,2) Y2=-cos(pi*N(:,:,1).*X(:,:,1)).*sin(pi*N(:,:,1).*T(:,:,k)); plot(x,Y2); axis([0,1,-1,1]) m2(:,k)=getframe; end movie(m1,1); movie(m2,1); 2. %画复变函数图形 %(z-0.5)1/2 z=cplxgrid(50); cplxmap(z,sqrt(z-0.5)) %画ez的图形 z=cplxgrid(50); cplxmap(z,exp(z)) %画lnz的图像 z=cplxgrid(50); cplxmap(z,log(z)) 3. %两端固定弦的级数解 %初速度为零，初位移不为零 clear;clc; function jxj N=50 t=0:0.005:2.0; x=0:0.001:1; ww=wfun(N,0); ymax=max(abs(ww)); h= plot(x,ww,linewidth,3); axis([ 0, 1, -ymax, ymax]) sy=[ ]; for n=2:length(t) ww=wfun(N,t(n)); set(h,ydata,ww); drawnow; sy=[sy,sum(ww)]; end function wtx=wfun(N,t) x=0:0.001:1; a=1; wtx=0; for I=1:N if I~=7 wtx=wtx+0.05*( (sin(pi*(7-I)*4/7)-sin(pi*(7-I)*3/7))... /(7-I)/pi-(sin(pi*(7+I)*4/7)-sin(pi*... (7+I)*3/7))/(7+I)/pi )*cos(I*pi*a*t).*sin(I*pi*x); else wtx=wtx+0.05