MATLAB程序设计教程课后答案.docx

1、MATLAB程序设计教程课后答案unit3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;otherwise p=E;endprice=p（2）n=input(请输入成绩);if n=90&n=80&n=70&n=60

2、&na 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=:;for n=1:61 a=b(n);y(n)=(exp*a)-exp*a)/2*sin(a+log(+a)/2);endy5y1=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

3、,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=0 disp(A(n,:);elseif n0 disp(lasterr);else disp(A(6,:); disp(lasterr);end 7（1）f=;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=i

4、nput(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=1,2,3,4,5;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

5、值：);for i=1:n y1=y1+-(-1)i/(2*i-1); y2=y2+1/4i;endy1y2unit4实验指导1（1）x=-10:10;y=x-x.3./6;plot(x,y)（2）x=-10:10; 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

6、,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）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);

7、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=1:20 axis(-i,i,-i,i,-i,i) m(:,i)=getframe;endmovie(m,4); 思考练习2（1）x=-5:5;y=(1./(2*pi).*exp(-(x.2)/2);plot(x,y);（2）t=-2*pi:2*pi;x=t.*sin(t);y=t.*cos(t);plot

8、(x,y);grid on;3t=0:pi/1000:pi;x=sin(3.*t).*cos(t);y1=sin(3.*t).*sin(t);y2=2.*;plot(x,y1,k,x,y2);hold on;k=find(abs(y1-y2) 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,xs

9、xh=sort(zong,descend)6x=1:10:101;y=0,;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=,;x=ApA=1/2,1/3,1/4;1/3,1/4,1/5;1/4,1/5,1/6;p=,;x=Apcond(A)2（1）x1=fzero(funx1,-1)function fx=funx1(x)fx=x41+x3+1;（2）x2=fzero(funx2,function fx=funx2

10、(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=ode23(fun4,t0,tf,y0);tyfunction yp=fun4(t,y)yp=-+sin(10*t)*y;（2）t0=0;tf=5;y0=1;t,y=ode23(fun5,t0,

11、tf,y0);tyfunction 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=fmincon(fun6,0,0,0,a,b,lb,ub)-fvalfunction f=fun6(x)f=-(sqrt(x(1)+(400-x(1)*+(sqrt(x(2)+(400-x(1)*(2)*+sqrt(3)+(400-x(1)*(2)*(3)*+sqrt(x(x4);思

12、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,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

13、);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;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

14、,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,;-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(f

15、x,0,2,1e-10)（2）format longfx=inline(1./(.2+-1./(.2+-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=:;F=,;trapz(X,F)4p=0:pi/5:2*pi;for n=1:3 n DX=diff(sin(p),n)end5f=inline(sin(x)./(x+cos(2.*x);g=inline(cos(x).*(x+cos(2*x)-si

16、n(x).*(1-2.*sin(2*x)/(x+cos(2.*x).2);x=-pi: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,)/; %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,Inf,1e-10)x=-100000:10

17、0000;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,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=0:2*pi;p=polyfi

18、t(x,f(x),5);dp=polyder(p);dpx=polyval(dp,x);dx=diff(f(x,2*pi+)/;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);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;

19、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)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

20、,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 bs1=2*(cos(x)2)-(sin(x)2;s2=sin(B1)*cos(B2)-cos(B1)*sin(B2);s3=sqrt(a+sqrt(a2-b)/2)+sqrt(a-sqrt(a2-b)/2);s4=(4*x2

21、+8*x+3)/(2*x+1);h1=simplify(s1)h2=simplify(s2)h3=simplify(s3)h4=simplify(s4)3syms x a;f=abs(x)/x;limit(f,x,0,left)f=(x+a/x)x;limit(f,x,inf)4syms x y mf=sqrt(x+sqrt(x+sqrt(x);m=diff(f,x)diff(m,x)syms x y;f=x+y-sqrt(x2+y2);z1=diff(f,x)z2=diff(f,y)5syms x y;f=x+y-sqrt(x2+y2);z1=diff(f,x)z2=diff(f,y)sym x;f=1/(asin(x)2*(1-x2)(1/2);int(f)6syms xf=1/(1+x);int(f,0,4)sym x;f=x3*sin(x)2/(x6+2*x4+1);int(f,-1,1)sym x;f=x3*sin(x)2/(x6+2*x4+1);int(f,-1,1)7syms ns=symsum(1/4n,1,inf)sym n;s=symsum(n+1)/n)(1/2),1,inf)eval(y)8syms x f=tan(x);taylor(f,x,3,0)s