程序设计教程后答案

1、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='D'othe

2、rwise p='E'endprice=p（2）n=input('请输入成绩');if n>=90&n<=100 p='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'endprice=p（3）try n;catch price='erroe'end3n=1,5,56,4

3、,3,476,45,6,3,76,45,6,4,3,6,4,23,76,908,6;a=n(1)；b=n(1);for m=2:20 if n(m)>a a=n(m); elseif n(m)<b b=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=1:61 a=b(n);y(n)=(exp(0.3*a)-exp(-0.3*a)/2*sin(a+0.3)+log(0.3+a)/2);endy5y1

4、=0;y2=1;n=input('请输入n的值：');for i=1:n y1=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>=0 disp(A(n,:);elseif n<0 disp(lasterr);else disp(A(6,:); disp(lasterr);end 7（1）f

5、=;for n=1:40 f(n)=n+10*log(n2+5);end y=f(40)/(f(30)+f(20)（2）f=;a=0;for n=1:40 f(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:n y=y+im;endy*function s=shi8_1(n,m)s=0;for i=1:n s=s+im;end*shi8_1(100,1)+shi8_1(50,2)+shi8_1(10,1/2)思考练习2N=1,2

6、,3,4,5;2.*NN./21./N1./N.23s=fix(100*rand(1,20)*9/10+10)y=sum(s)/20j=0;for i=1:20 if s(i)<y&rem(s(i),2)=0 j=j+1; A(j)=s(i); else continue; endendA4y1=0;y2=0;n=input('请输入n的值：');for i=1:n y1=y1+-(-1)i/(2*i-1); y2=y2+1/4i;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:

7、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);subplot(2,2,3);stem(t,y,'k');title('杆图(t,y)');axis(-pi,p

8、i,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）t=-pi/3:pi/50:pi/3;r=5.*(sin(t).2)./cos(t);polar(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

9、）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=1:20 axis(-i,i,-i,i,-i,i) m(:,i)=getframe;endmovie(m,4); 思考练习2（1）x=-5:0.1:5;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,

10、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;k=find(abs(y1-y2)<1e-2);x1=x(k);y3=2.*x1-0.5;plot(x1,y3,'rp');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*

11、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);x=3.*u.*sin(v);y=2.*u.*cos(v);z=4.*u.2;subplot(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+

12、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)Sumhang=sum(A,2)SumA=sum(Sumhang)B=sort(A);C=sort(B,2,'descend');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：');

13、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=1,9,16,25,36,49,64,81,100;N=sqrt(n);x=input('ji suan zhi : ');interp1(n,N,x,'cubic')3N=64;T=5;t=linspace(0,T,N);h

14、=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)5P1=1,2,4,0,5;P2=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)

15、Max=max(A)Min=min(A)n=0;for i=1:30000 if(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,1,1)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,

16、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;1/4,1/5,1/6;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)fu

17、nction 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(fun3,1,1,1',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=ode

18、23(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)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=fmin

19、con(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(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=in

20、v(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(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);y=p(2);q(1)=x2+y2-9;q(2)=x+y-1;3（1）t0=0

21、;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)=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=

22、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);-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)-

23、6');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('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=1:3 n DX=diff(sin(p),n)end5f=inline('sin(x).

24、/(x+cos(2.*x)');g=inline('(cos(x).*(x+cos(2*x)-sin(x).*(1-2.*sin(2*x)/(x+cos(2.*x).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2form

25、at longfx=inline('1./(1+x.2)');I,n=quad(fx,-Inf,Inf,1e-10)I,n=quadl(fx,-Inf,Inf,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)(2)format longfx=inline('sqrt(cos(t.2)+4*sin(2*t).2)+1)');I,n=quad(fx,

26、0,2*pi,1e-10)4f=inline('4.*x.*z.*exp(-z.2.*y-x.2)');I=triplequad(f,0,pi,0,pi,0,1)5f=inline('sin(x)');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

27、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);limit(f,x,-1,'right')3sym x;f=sin(1/x);diff(f,'x')diff(f,'x',2)sym x;f=(1-cos(2*x)/x;diff(f,'x')diff(f,'x',2)4sym x;f=sqrt(exp(x)+1);int(f,'x

28、')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)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

29、=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 bs1=2*(cos(x)2)-(sin(x)2;s2=sin(B1)*cos(B2)-cos(B