matlab上机习题详解-试题答案.doc

1、P第一次实验答案 1 设要求以0.01秒为间隔，求出y的151个点，并求出其导数的值和曲线。clcclearx=0:0.01:1.5;y=sqrt(3)/2*exp(-4*x).*sin(4*sqrt(3)*x+pi/3)y1=diff(y)subplot(2,1,1)plot(x,y)subplot(2,1,2)plot(x(1:150),y1)2绘制极坐标系下曲线（a,b,n自定数据）clccleara=10;b=pi/2;n=5;theta=0:pi/100:2*pi;rho=a*cos(b+n*theta);polar(theta,rho)3. 列出求下列空间曲面交线的程序clccle

2、arx=-5:0.5:5;X,Y=meshgrid(x);z1=X.2-2*Y.2;z2=X.*2-Y.*3;xlabel(x)ylabel(y)zlabel(z)surf(X,Y,z1)hold onsurf(X,Y,z2)k=find(abs(z1-z2)2 error(输入量太多。);else S=N*R*R*sin(2*pi/N)/2; L=2*N*R*sin(pi/N); plot(x,y,str) endaxis equal squarebox on3、编写一个学生成绩管理的程序，完成下列功能：(1) 构造一个学生结构，包括学生的姓名，课程名称（限M门），考试成绩和平均值等域； (

3、2) 从键盘上，连续输入N个学生的情况，分别将这些学生的情况填入到相应的域，若域中没有值即为空或0，并分别计算其平均值写入到其平均值域。(3) 根据平均值排序（由高到低），并输出学生的姓名和平均值。clcclearn=input(please input students number:);for x=1:n number(x)=struct(name,Curriculum1,Curriculum2,Curriculum3,Average,);endfor i=1:n number(i).name=input(name:,s); number(i).Curriculum1=input(plea

4、se input the scoresnCurriculum1:); number(i).Curriculum2=input(Curriculum2:); number(i).Curriculum3=input(Curriculum3:); number(i).Average=(number(i).Curriculum1+number(i).Curriculum2+number(i).Curriculum3)/3; disp(the average is:) disp(num2str(number(i).Average)end NameCell=cell(1,n);Array=1,n;for

5、i=1:n NameCell(1,i)=number(i).name; Array(i)=number(i).Average;endfor j=1:(n-1) iptr = j; for i=(j+1):n if Array(i)Array(iptr) %比较相邻前后大小 iptr=i; end end if j=iptr %若后面比前面大，互换 Name=NameCell(1,i); NameCell(1,i)=NameCell(1,j); NameCell(1,j)=Name; average=Array(i); Array(i)=Array(j); Array(j)=average; j

6、=1; iptr=j; endenddisp(成绩排序如下：)for i=1:n disp(strcat(名次: ,num2str(i), 名字 ,NameCell(1,i), 平均成绩: ,num2str(Array(i)end 4、使用句柄图像对象绘制曲线：y=2e-0.5xcos(x)，同时对曲线进行标注和修饰。x=-12:0.02:12y=2*exp(-0.5)*x).*cos(pi*x)h_f=figure(Position,200 300 300 300,menubar,none)h_a1=axes(position,0.1,0.1,.8,.8)h_t=title(h_a1,函数=

7、2*exp(-0.5)*x).*cos(pi*x)h_1=line(x,y)set(gca,xtick,(-6)*pi (-4)*pi (-2)*pi 0 (2)*pi (4)*pi (6)*pi)set(gca,xticklabel,(-6)*pi, (-4)*pi, (-2)*pi, 0, (2)*pi, (4)*pi,(6)pi)set(gca,xgrid,on,ygrid,on)set(h_1,linewidth,2)set(get(h_t,parent),color,y)h_anm1=annotation(gcf,rectangle,0.1 0.5 .8 0.4,FaceAlpha,

8、.7,FaceColor,red)第三次试验答案1、做一个带按钮的界面，当按动“播放”按钮时调入声音文件并播放，显示声音波形，并建立一个用于关闭界面的按钮对象。（提示，找一个.wav文件，简单起见可以在windows目录下找一个文件，将其放在当前工作目录下或搜索路径上。具体用法请参照：y,f,b=wavread(*.wav); % 读入声音文件sound(y,f,b) % 由声卡播放声音plot(y) % 画出波形2、创建一个用于绘图参数选择的菜单对象，其中包含三个选项LineStyle、Marker和Color，每个选项下面又包含若干的子项分别可以进行选择图线的类型、标记点的类型和颜色 (每

9、个子项不少于3个)，当按下“绘图”按钮时，根据选项绘制正弦曲线（缺省时为蓝色无标记实线）。（注意使用全球变量）function varargout = shiyan32(varargin)% SHIYAN32 MATLAB code for shiyan32.fig% Begin initialization code - DO NOT EDITgui_Singleton = 1;gui_State = struct(gui_Name, mfilename, . gui_Singleton, gui_Singleton, . gui_OpeningFcn, shiyan32_OpeningFc

10、n, . gui_OutputFcn, shiyan32_OutputFcn, . gui_LayoutFcn, , . gui_Callback, );if nargin & ischar(varargin1) gui_State.gui_Callback = str2func(varargin1);end if nargout varargout1:nargout = gui_mainfcn(gui_State, varargin:);else gui_mainfcn(gui_State, varargin:);end% End initialization code - DO NOT E

11、DIT % - Executes just before shiyan32 is made visible.function shiyan32_OpeningFcn(hObject, eventdata, handles, varargin)% This function has no output args, see OutputFcn.% hObject handle to figure% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and

12、user data (see GUIDATA)% varargin command line arguments to shiyan32 (see VARARGIN) % Choose default command line output for shiyan32handles.output = hObject; % Update handles structureguidata(hObject, handles); % UIWAIT makes shiyan32 wait for user response (see UIRESUME)% uiwait(handles.figure1);g

13、lobal cc=bglobal ll=-global mm= % - Outputs from this function are returned to the command line.function varargout = shiyan32_OutputFcn(hObject, eventdata, handles) % varargout cell array for returning output args (see VARARGOUT);% hObject handle to figure% eventdata reserved - to be defined in a fu

14、ture version of MATLAB% handles structure with handles and user data (see GUIDATA) % Get default command line output from handles structurevarargout1 = handles.output; % -function Untitled_1_Callback(hObject, eventdata, handles)% hObject handle to Untitled_1 (see GCBO)% eventdata reserved - to be de

15、fined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)global l % -function Untitled_8_Callback(hObject, eventdata, handles)% hObject handle to Untitled_8 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with hand

16、les and user data (see GUIDATA)global m % -function color_Callback(hObject, eventdata, handles)% hObject handle to color (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)global c % -function Untitled_14_Callback(h

17、Object, eventdata, handles)% hObject handle to Untitled_14 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)global cc=r % -function Untitled_15_Callback(hObject, eventdata, handles)% hObject handle to Untitled_15

18、(see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)global cc=b % -function Untitled_16_Callback(hObject, eventdata, handles)% hObject handle to Untitled_16 (see GCBO)% eventdata reserved - to be defined in a future

19、version of MATLAB% handles structure with handles and user data (see GUIDATA)global cc=g % -function Untitled_17_Callback(hObject, eventdata, handles)% hObject handle to Untitled_17 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user

20、data (see GUIDATA) global cc=y% -function Untitled_10_Callback(hObject, eventdata, handles)% hObject handle to Untitled_10 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)global mm=o % -function Untitled_11_Callb

21、ack(hObject, eventdata, handles)% hObject handle to Untitled_11 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)global mm=* % -function Untitled_13_Callback(hObject, eventdata, handles)% hObject handle to Untitle

22、d_13 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA) global mm=d % -function Untitled_4_Callback(hObject, eventdata, handles)% hObject handle to Untitled_4 (see GCBO)% eventdata reserved - to be defined in a fut

23、ure version of MATLAB% handles structure with handles and user data (see GUIDATA)global ll=- % -function Untitled_5_Callback(hObject, eventdata, handles)% hObject handle to Untitled_5 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and use

24、r data (see GUIDATA)global ll=- % -function Untitled_7_Callback(hObject, eventdata, handles)% hObject handle to Untitled_7 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)global ll=-. % - Executes on button press

25、 in pushbutton1.function pushbutton1_Callback(hObject, eventdata, handles)% hObject handle to pushbutton1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)global s global l global m global cx=0:0.1:2*pi;y=sin(x);s

26、=strcat(l,m,c);plot(x,y,s)2. 设和是两个10行10列的矩阵（数组），试说明命令A*B, A/B, AB, A.*(B.A), A./B, A.B和sin(A).*exp(B)的涵义。A,B的矩阵乘法，矩阵A乘以B的逆，矩阵B乘以A的逆，B的每个元素的对应A次幂乘以A对应的每个元素A的每个元素除以B对应的每个元素，B的每个元素除以A对应的每个元素，A的每个元素的正弦与B对应的每个元素的指数求积，3. 设A为数组，B为一个行数大于3的数组，请给出（1）删除A的第4、8、12三列的命令； （2）删除B的倒数第3行的命令；（3）求符号极限的命令集； （4）求的3阶导数的命令

27、集；（5）计算定积分的命令，并给出计算结果(!)A(:,4 8 12)=(2)B(end-2)=(3)syms m n xlimit(tan(m*x)/(n*x)（4）syms x yy=atan(x+3)/(x-2)-log(1+exp(-2)*x)diff(y,3)(5)syms xint(abs(x)+sin(x)*x2,-1,1)得分 三基本编程题（每小题10分，共30分）1. Write a program to compute the following expressions;Here, we suppose the variable x has existed in the w

28、orkspace.for i=1:10 for j=1:10xbar(i)=xbar(i)+x(i,j); end xbar(i)=xbar(i)/10;endfor i=1:10 for j=1:10 t1=0;t2=0;t3=0; for k=1:3 t1=t1+(x(i,k)-xbar(i)*(x(j,k)-xbar(j); t2=t2+(x(i,k)-xbar(i)2; t3=t3+(x(j,k)-xbar(j)2; end r2(i,j)=t1/sqrt(t2*t3); endendr2 2. (1) Using plot() function to plot the curves

29、of and in the range of , let their color are red and green respectively, and add the grid to the figure. (2) Using fplot() function and ezplot() function to plot above-mentioned (上述的) curves respectively.(1)x=-2*pi:pi/100:2*pi;y=(sin(2*x)+cos(3*x).*exp(-2*x);z=sin(x)/x;plot(x,y,r,x,z,g)（2）fplot(sin(

30、2*x)+cos(3*x).*exp(-2*x), sin(x)/x,-2*pi 2*pi) 3. Plot the 3D mesh figure and 3D surface figure of the functionin the range of and , respectively.x=-4:1/100:4;y=-4:1/100:4;z=9(1-x)2*exp(-x2/2-(y+1)2)mesh(x,y,z);surf(x,y,z);得分 四综合编程题（每小题11分，共22分） 1. Write a function program to compute the following f

31、unctionand call this function program to compute the value of in main program or command window, there, shows the factorial (阶乘) of . 提示：对x取整的函数有fix(x), floor(x), round(x) 和ceil(x) .fuction y=f1(x) %f1.mif x-fix(x)= =0y=prod(1:abs(2*x);elsey=4*sin(2*x)+x1.8；y=f1(-4)+f1(3)-f1(14.37)2.Write a program

32、to compute the sample mean,and the sample skewness (偏度) .for the following three case:(1) n and exist in Workspace of Matlab. It is no any limit;(2) n and are unknown variables. Please input x by keyboard one by one, and give a mark of end the data input. Examinees can use loop statement and length(

33、) function and input() function, but cannot use mean() function, std() function, and var() function directly （可以使用循环语句和length()函数、input()函数等进行编程，但不能直接使用mean()、std()和var()等函数）. (1)s=0;for i=1:ns=s+x(i);endxbar=s/nm=0;for i=1:nm=m+(x(i)-xbar)3;endske=m/n(2)x(1)=input(请输入x );i=1;s=0;while(x(i)=a) s=s+x

34、(i); i=i+1; x(i)=input(请输入x ,输a结束);endxbar=s/(i-1)m=0;for j=1:i-1m=m+(x(i)-xbar)3;endske=m/(i-1)一、填空题1、MATLAB常用操作界面包括 命令窗口 、工作空间窗口、 命令历史窗口 、当前目录窗口 、内存数组编辑器、M文件编辑/调试器、帮助导航/浏览器、图形窗口等。2、MATLAB中Inf或inf表示 无穷大 、NaN或nan表示 不是一个数 、nargout表示 函数输出变量数目 。3、工作空间浏览器主要用于内存变量的 查阅 、 保持 和 编辑 。4、MATLAB实现将全下标转换为单下标的指令为 sub2ind 、据单下标换算出全下标的指令为 ind2sub 。5、MATLAB中clf用于 清除图形窗口 、clc用于 清除指令窗口中显示内容 、clear用于 清除MATLAB工作空间中保存的变量 。二、简答题（每题5分，共20分） 1、简述MATLAB历史指令窗的主要作用。答：历史指令窗记录着用户在MATLAB指令窗中所输入过的所有指令。历史记录包括：每次开启MATLAB的时间，每次开启MATLAB后在指令窗中运行过的所有指令。应用功能有单行或多行指令的复制和运行、生成M文件等。2、简述MATLAB函数的基本结构。答：典型M函数文件的结构：