聊城大学通信工程专业matlab编程题答案.doc

1. 阶乘的函数(函数文件)function result=jiecheng(n)result=1;for i=1:n result=result*i;end(脚本文件)n=input(输入n:);result=jiecheng(n);disp(阶乘结果是:);result2. 编写一个计算双曲正弦的函数。以及调用这个函数的脚本m文件。(函数文件)function sinhxx=-7:0.1:7;y=(exp(x)-exp(-x)/2;plot(x,y);title(plot of (exp(x)-exp(-x)/2);xlabel(x);ylabel(y);legend(双曲正弦);grid on;（脚本文件）disp(双曲正弦函数);sinhx3. 成绩(函数文件)。function result=paixu(a)result=a;for i=1:length(result); for j=2:length(result); if result(j-1)result(j); q=result(j-1); result(j-1)=result(j); result(j)=q; end endend(脚本文件)for i=1:10; a(i)=input(输入a:); endazuigao=max(a)zuidi=min(a)pingjun=mean(a)result=paixu(a)4.分段函数的表示。(脚本文件)disp(输入x,y:);x=input(输入x:);y=input(输入y:);if x = 0 & y = 0;fun = x + y;elseif x = 0 & y 0;fun = x + y2;elseif x = 0;fun = x2 + y;elsefun = x2 + y2;endfun5.求一元二次方程的根（讨论系数）。（脚本文件）disp(输入a,b,c);a=input(输入a：);b=input(输入b：);c=input(输入c：);if(b2-4*a*c)0; x1=(-b)/(2*a)-sqrt(b2-4*a*c)/(2*a); x2=(-b)/(2*a)+sqrt(b2-4*a*c)/(2*a);endx1x26. 如何修改程序能使小红球上下不停运动x=0:0.01:20*pi;p=plot3(sin(x),cos(x),x);h=line(0,1,0,color,red,marker,.,markersize,20,erasemode,xor);for k=0:0.01:20*pi; set(h,xdata,sin(k),ydata,cos(k),zdata,k); drawnow;endfor k=20*pi:-0.01:0; set(h,xdata,sin(k),ydata,cos(k),zdata,k); drawnow;endclear close all y = dsolve ( D2y+3*Dy+2*y=2*t+2*t2,y(0)=1,Dy(0)=1);yht = dsolve ( D2y+3*Dy+2*y=0);yt = dsolve ( D2y+3*Dy+2*y=2*t+2*t2);yp = yt-yht;yh = y-yp;yzi= dsolve ( D2y+3*Dy+2*y=0,y(0)=1,Dy(0)=1);yzs= dsolve ( D2y+3*Dy+2*y=2*t+2*t2,y(0)=1,Dy(0)=1);t=0:0.01:3;figure(1)ezplot(yzi,0,3);hold on ;ezplot(yzs,0,3);ezplot(y,0,3);axis(0 3 -1 5);hold off;title(全响应，零输入响应，零状态响应 )；figure(2)ezplot(yh,0,3);hold on ;ezplot(yp,0,3);ezplot(y,0,3);axis(0 3 -1 5);hold off;title（全响应，自由响应，强迫响应）clear;close all;N=64;n=0:N-1;A=3 -4 2;B=1 2;x1=(1/2).n;y=filter(B,A,x1);x2=n=0;h=filter(B,A,x2);subplot(2,1,1);stem(n,y,fill);grid on;xlabel(n);title(系统响应y(n);subplot(2,1,2);stem(n,h,fill);grid on;xlabel(n);title(系统单位取样响应h(n);clear； close all； y = dsolve ( D2y+3*Dy+2*y=2*t+2*t2,y(0)=1,Dy(0)=1);% 自由响应和强迫响应yht = dsolve ( D2y+3*Dy+2*y=0);%求齐次通解yt = dsolve ( D2y+3*Dy+2*y=2*t+2*t2); %求非齐次通解yp = yt-yht;%求特解，即强迫响应yh = y-yp;%求齐次解，即自由响应yzi= dsolve ( D2y+3*Dy+2*y=0,y(0)=1,Dy(0)=1);%求零输入相应yzs= dsolve ( D2y+3*Dy+2*y=2*t+2*t2,y(0)=1,Dy(0)=1);%求零状态响应t=0:0.01:3;figure(1)ezplot(yzi,0,3);hold on ;ezplot(yzs,0,3);ezplot(y,0,3);axis(0,3；-1，5);hold off;title(全响应，零输入响应，零状态响应 )；figure(2)ezplot(yh,0,3);hold on ;ezplot(yp,0,3);ezplot(y,0,3);axis(0,3；-1，5);hold off;title（全响应，自由响应，强迫响应）clear;close all;N=64;n=0:N-1;A=3 -4 2;B=1 2;x1=(1/2).n;y=filter(B,A,x1);x2=n=0;h=filter(B,A,