MATLAB程序设计教程(第二版)课后答案

1、学习资料收集于网络，仅供参考MATLAB第二版课后答案unit3-8unit3实验指导1、 n=input('请输入一个三位数：');a=fix(n/100);b=fix(n-a*100)/10);c=n-a*100-b*10;d=c*100+b*10+a2（ 1）n=input('请输入成绩 ');switch ncase num2cell(90:100)p='A'case num2cell(80:89)p='B'case num2cell(70:79)p='C'case num2cell(60:69)p=

2、9;D'otherwisep='E'endprice=p（ 2） n=input(' 请输入成绩 '); if n>=90&n<=100p='A'elseif n>=80&n<=89 p='B'elseif n>=70&n<=79 p='C'elseif n>=60&n<=69 p='D'else p='E'end price=p（ 3） try n;catchprice='erroe&#

3、39;end3n=1,5,56,4,3,476,45,6,3,76,45,6,4,3,6,4,23,76,908,6;学习资料学习资料收集于网络，仅供参考a=n(1)；b=n(1);for m=2:20if n(m)>aa=n(m);elseif n(m)<bb=n(m);endendmax=amin=b法 2n=1,5,56,4,3,476,45,6,3,76,45,6,4,3,6,4,23,76,908,6;min=min(n)max=max(n)4b=-3.0:0.1:3.0;for n=1:61a=b(n);y(n)=(exp(0.3*a)-exp(-0.3*a)/2*si

4、n(a+0.3)+log(0.3+a)/2);endy5y1=0;y2=1;n=input(' 请输入 n 的值： ');for i=1:ny1=y1+1/i2;y2=y2*(4*i*i)/(2*i-1)*(2*i+1);endy1y26A=1,1,1,1,1,1;2,2,2,2,2,2;3,3,3,3,3,3;4,4,4,4,4,4;5,5,5,5,5,5;6,6,6,6,6,6;n=input(' 请输入 n 的值 :');if n<=5&n>=0disp(A(n,:);elseif n<0disp(lasterr);else di

5、sp(A(6,:);disp(lasterr);end7（ 1）f=;学习资料学习资料收集于网络，仅供参考for n=1:40f(n)=n+10*log(n2+5);endy=f(40)/(f(30)+f(20)（ 2）f=;a=0;for n=1:40f(n)=a+n*(n+1);a=f(n);endy=f(40)/(f(30)+f(20)8y=0;m=input(' 输入 m 的值 :');n=input(' 输入 n 值： ');for i=1:ny=y+im;endy*function s=shi8_1(n,m)s=0;for i=1:ns=s+im;e

6、nd*shi8_1(100,1)+shi8_1(50,2)+shi8_1(10,1/2)思考练习2N=1,2,3,4,5;2.*NN./21./N1./N.23s=fix(100*rand(1,20)*9/10+10)y=sum(s)/20j=0;for i=1:20if s(i)<y&rem(s(i),2)=0j=j+1;A(j)=s(i);else continue;end学习资料学习资料收集于网络，仅供参考endA4y1=0;y2=0;n=input(' 请输入 n 的值： ');for i=1:ny1=y1+-(-1)i/(2*i-1);y2=y2+1/4

7、i;endy1y2unit4实验指导1（ 1）x=-10:0.05:10;y=x-x.3./6;plot(x,y)（ 2）x=-10:0.5:10;ezplot('x2+2*y2-64',-8,8);grid on;2t=-pi:pi/10:pi;y=1./(1+exp(-t);subplot(2,2,1);bar(t,y);title(' 条形图 (t,y)');axis(-pi,pi,0,1);subplot(2,2,2);stairs(t,y,'b');title(' 阶梯图 (t,y)');axis(-pi,pi,0,1)

8、;subplot(2,2,3);stem(t,y,'k');title(' 杆图 (t,y)');axis(-pi,pi,0,1);subplot(2,2,4);loglog(t,y,'y');title(' 对数坐标图 (t,y)');3（ 1）t=0:pi/50:2*pi;r=5.*cos(t)+4;polar(t,r);title('rho=5*costheta+4');（ 2）学习资料学习资料收集于网络，仅供参考t=-pi/3:pi/50:pi/3;r=5.*(sin(t).2)./cos(t);polar

9、(t,r);4（ 1）t=0:pi/50:2*pi;x=exp(-t./20).*cos(t);y=exp(-t./20).*sin(t);z=t;plot3(x,y,z);grid on;（ 2）x,y=meshgrid(-5:5);z=zeros(11)+5;mesh(x,y,z);shading interp;5x,y,z=sphere(20);surf(x,y,z);axis off;shading interp;m=moviein(20);for i=1:20axis(-i,i,-i,i,-i,i)m(:,i)=getframe;endmovie(m,4);思考练习2（ 1）x=-5

10、:0.1:5;y=(1./(2*pi).*exp(-(x.2)/2);plot(x,y);（ 2）t=-2*pi:0.1:2*pi;x=t.*sin(t);y=t.*cos(t);plot(x,y);grid on;3t=0:pi/1000:pi;x=sin(3.*t).*cos(t);y1=sin(3.*t).*sin(t);y2=2.*x-0.5;plot(x,y1,'k',x,y2);hold on;学习资料学习资料收集于网络，仅供参考k=find(abs(y1-y2)<1e-2);x1=x(k);y3=2.*x1-0.5;plot(x1,y3,'rp

11、9;);4x=-2:0.01:2;y=sin(1./x);subplot(2,1,1);plot(x,y);subplot(2,1,2);fplot('sin(1./x)',-2,2,1e-4);5（ 1）i=-4*pi:0.1:10;j=12./sqrt(i);polar(i,j);title('rho=12/sqrt(theta)')（ 2）a=-pi/6:0.01:pi/6;b=3.*asin(a).*cos(a)./(sin(a).3+(cos(a).3);polar(a,b);6（ 1）u,v=meshgrid(-4:0.1:4);z=4.*u.2;s

12、ubplot(2,1,1);mesh(x,y,z);subplot(2,1,2);surf(x,y,z);（ 2）x,y=meshgrid(-3:0.2:3);z=-5./(1+x.2+y.2);subplot(1,2,1);mesh(x,y,z);subplot(1,2,2);surf(x,y,z);unit5实验指导1A=randn(10,5)x=mean(A)y=std(A)Max=max(max(A)Min=min(min(A)学习资料学习资料收集于网络，仅供参考Sumhang=sum(A,2)SumA=sum(Sumhang)B=sort(A);C=sort(B,2,'des

13、cend');C2（ 1）a=0:15:90;b=a./180.*pi;s=sin(b)c=0:15:75;d=c./180.*pi;t=tan(d)e=input(' 请输入想计算的值：');S=sin(e/180*pi)T=tan(e/180*pi)S1=interp1(a,s,e,'spline')T1=interp1(c,t,e,'spline')P1=polyfit(a,s,5);P2=polyfit(c,t,5);S2=polyval(P1,e)T2=polyval(P2,e)（ 2）n=1,9,16,25,36,49,64,

14、81,100;N=sqrt(n);x=input('ji suan zhi : ');interp1(n,N,x,'cubic')3N=64;T=5;t=linspace(0,T,N);h=exp(-t);dt=t(2)-t(1);f=1/dt;X=fft(t);F=X(1:N/2+1);f=f*(0:N/2)/N;plot(f,abs(F),'-*')4P=2,-3,0,5,13;Q=1,5,8;p=polyder(P)q=polyder(P,Q)a,b=polyder(P,Q)学习资料学习资料收集于网络，仅供参考5P1=1,2,4,0,5;P

15、2=0,1,2;P3=1,2,3;P=P1+conv(P2,P3)X=roots(P)A=-1,1.2,-1.4;0.75,2,3.5;0,5,2.5;p=polyval(P,A)思考练习4A=rand(1,30000);a=mean(A)b=std(A)Max=max(A)Min=min(A)n=0;for i=1:30000if(A(i)>0.5)n=n+1;endendny=n/300005p=45,74,54,55,14;78,98,45,74,12;87,98,85,52,65M,S=max(p)N,H=min(p)junzhi=mean(p,1)fangcha=std(p,1

16、,1)zong=sum(p,2);Max,wei=max(zong)Min,wei=min(zong)zcj,xsxh=sort(zong,'descend')6x=1:10:101;y=0,1.0414,1.3222,1.4914,1.6128,1.7076,1.7853,1.8513,1.9085,1.9590,2.0043;p,s=polyfit(x,y,5)a=1:5:101;y1=polyval(p,a);plot(x,y,':o',a,y1,'-*')unit6实验指导1A=1/2,1/3,1/4;1/3,1/4,1/5;1/4,1/

17、5,1/6;学习资料学习资料收集于网络，仅供参考p=0.95,0.67,0.52'x=ApA=1/2,1/3,1/4;1/3,1/4,1/5;1/4,1/5,1/6;p=0.95,0.67,0.53'x=Apcond(A)2（ 1）x1=fzero(funx1,-1)function fx=funx1(x)fx=x41+x3+1;（ 2）x2=fzero(funx2,0.5)function fx=funx2(x)fx=x-sin(x)/x;（ 3）options=optimset('Display','off');x=fsolve(fun3,1

18、,1,1',options)q=fun3(x)function q=fun3(p)x=p(1);y=p(2);z=p(3);q(1)=sin(x)+y2+log(z)-7;q(2)=3*x+2y-z3+1;q(3)=x+y+z-5;3（ 1）t0=0;tf=5;y0=1;t,y=ode23(fun4,t0,tf,y0);t'y'function yp=fun4(t,y)yp=-(1.2+sin(10*t)*y;（ 2）t0=0;tf=5;y0=1;t,y=ode23(fun5,t0,tf,y0);t'y'function yp=fun5(t,y)学习资料

19、学习资料收集于网络，仅供参考yp=cos(t)-y/(1+t2);4x=fminbnd(mymin,0,2);-mymin(x)function fx=mymin(x)fx=-(1+x.2)/(1+x.4);5options=optimset('Display','off');x,fval=fmincon(fun6,0,0,0,a,b,lb,ub)-fvalfunction f=fun6(x)f=-(sqrt(x(1)+(400-x(1)*1.1+(sqrt(x(2)+(400-x(1)*1.1-x(2)*1.1+sqrt(3)+(400-x(1)*1.1-x(

20、2)*1.1-x(3)*1.1+sqrt(x(x4);思考练习1（ 1）A=2,3,5;3,7,4;1,-7,1;B=10,3,5'C1=inv(A)*BC2=ABL,U=lu(A);x=U(LB)（ 2）A=6,5,-2,5;9,-1,4,-1;3,4,2,-2;3,-9,0,2;B=-4,13,1,11'C1=inv(A)*BC2=ABL,U=lu(A);x=U(LB)2（ 1）x1=fzero(funx1,1.5)function fx=funx1(x)fx=3*x+sin(x)-exp(x);（ 2）x1=fzero(funx2,1)function fx=funx2(

21、x)fx=x-1/x+5;（ 3）options=optimset('Display','off');x=fsolve(fun3,3,0',options)q=fun3(x)function q=fun3(p)x=p(1);学习资料学习资料收集于网络，仅供参考y=p(2);q(1)=x2+y2-9;q(2)=x+y-1;3（ 1）t0=0;tf=5;y0=0,1;t,y=ode45(vdpol,t0,tf,y0);t,yfunction ydot=vdpol(t,y);ydot(1)=(2-3*y(2)-2*t*y(1)./(1+t2);ydot(2)=

22、y(1);ydot=ydot'（ 2）t0=0;tf=5;y0=1;0;2;t,y=ode45(vdpoll,t0,tf,y0);t,yfunction ydot=vdpoll(t,y);ydot(1)=cos(t)-y(3)./(3+sin(t)+5*y(1).*cos(2*t)/(t+1).2)-y(2);ydot(2)=y(1);ydot(3)=y(2);ydot=ydot'4x=fminbnd(mymin,0,pi);-mymin(x)function fx=mymin(x)fx=-sin(x)-cos(x.2);5x,y1=fminbnd(mymax,0,1.5);-

23、y1function fx=mymax(x);fx=-(9*x+4*x.3-12*x.2);unit7实验指导1（ 1）format longfx=inline('sin(x)./x');I,n=quadl(fx,0,2,1e-10)（ 2）format longfx=inline('1./(x-0.3).2+0.01)-1./(x-0.9).2+0.04)-6');学习资料学习资料收集于网络，仅供参考I,n=quad(fx,0,1,1e-10)2（ 1）global ki;ki=0;I=dblquad(fxy,0,1,0,1)ki（ 2）f=inline(&#

24、39;abs(cos(x+y)','x','y');I=dblquad(f,0,pi,0,pi)3X=0.3:0.2:1.5;F=0.3895,0.6598,0.9147,1.1611,1.3971,1.6212,1.8325;trapz(X,F)4p=0:pi/5:2*pi;for n=1:3nDX=diff(sin(p),n)end5f=inline('sin(x)./(x+cos(2.*x)');g=inline('(cos(x).*(x+cos(2*x)-sin(x).*(1-2.*sin(2*x)/(x+cos(2.*x

25、).2'); x=-pi:0.01:pi;p=polyfit(x,f(x),5);dp=polyder(p);dpx=polyval(dp,x);%求 dp 在假设点的函数值dx=diff(f(x,3.01)/0.01;%直接对 f(x) 求数值导数gx=g(x);%求函数 f 的导函数g 在假设点的导数plot(x,dpx,x,dx,'.',x,gx,'-');%作图思考练习2format longfx=inline('1./(1+x.2)');I,n=quad(fx,-Inf,Inf,1e-10)I,n=quadl(fx,-Inf,I

26、nf,1e-10)x=-100000:100000;y=1./(1+x.2);trapz(x,y)format short3(1)format longfx=inline('log(1+x)./(1+x.2)');I,n=quad(fx,0,1,1e-10)学习资料学习资料收集于网络，仅供参考(2)format longfx=inline('sqrt(cos(t.2)+4*sin(2*t).2)+1)');I,n=quad(fx,0,2*pi,1e-10)4I=triplequad(f,0,pi,0,pi,0,1)5f=inline('sin(x)

27、9;);g=inline('cos(x)');x=0:0.01:2*pi;p=polyfit(x,f(x),5);dp=polyder(p);dpx=polyval(dp,x);dx=diff(f(x,2*pi+0.01)/0.01;gx=g(x);plot(x,dpx,x,dx,'.',x,gx,'-')unit8实验指导1syms x y;s=x4-y4;factor(s)factor(5135)2syms x;f=(x-2)/(x2-4);limit(f,x,2)sym x;f=(sqrt(pi)-sqrt(acos(x)/sqrt(x+1

28、);limit(f,x,-1,'right')3sym x;f=sin(1/x);diff(f,'x')diff(f,'x',2)sym x;学习资料学习资料收集于网络，仅供参考f=(1-cos(2*x)/x;diff(f,'x')diff(f,'x',2)4sym x;f=sqrt(exp(x)+1);int(f,'x')syms x y;f=x/(x+y);int(f,'y')sym x;f=exp(x)*(1+exp(x)2;int(f,'x',0,log(2)

29、sym x;f=x*log(x);int(f,'x',1,exp(1)5sym x;s=symsum(-1)(x+1)/x,1,Inf)sym y;z=symsum(y(2*y-1)/(2*y-1),1,Inf)6sym x;f1=(exp(x)+exp(-x)/2;f2=sqrt(x3-2*x+1);taylor(f1,x,5,0)taylor(f2,x,6,0)7syms x y a;x=solve('x3+a*x+1=0','x')x=solve('sin(x)+2*cos(x)-sqrt(x)=0','x')x y=solve('log(x/y)=9','exp(x+y)=3','x','y')8syms n;x,y=dsolve('x*(D2y)+(1-n)*(Dy)+y=0','y(0)=0','Dy(0)=0','x')思考练习2syms x B1 B2 a b学习资料学习资料收集于网络，仅供参考s1=2*(cos(x)2)-(sin(x)2;s2=sin(B1)*cos(B2)-