《北京科技大学matlab数学实验期末考试题目及答案》由会员分享，可在线阅读，更多相关《北京科技大学matlab数学实验期末考试题目及答案（20页珍藏版）》请在金锄头文库上搜索。
1、第1张1.figure(1)x=-pi:pi/50:pi;y=cos(2*(x.2);plot(x,y,r-.)figure(2)x=-pi:pi;y=cos(2*(x.2);xi=-pi:pi/8:pi;yi1=interp1(x,y,xi,*nearest);yi2=interp1(x,y,xi,*linear);yi3=interp1(x,y,xi,*spline);yi4=interp1(x,y,xi,*cubic);plot(x,y,ro,xi,yi1,-,xi,yi2,-,xi,yi3,k.-,xi,yi4,m:)2.functionxdot=exf(t,x)u=t3;xdot=0
2、 1;-5 0*x+0 3*u;clf,t0=0;tf=10;x0t=1;2;t,x=ode23(exf,t0,tf,x0t)y1=x(:,1),y2=x(:,2);plot(t,y1,-,t,y2,o)第2张1.第一张dsolve(D2y+4*y=t*cos(t),y(0)=1,Dy(0)=1,t)第二张 functionxdot=exf(t,x)u=t*cos(t);xdot=0 1;-4 0*x+0 1*u;第三张t0=0;tf=10;x0t=1;1;t,x=ode23(exf,t0,tf,x0t)y1=x(:,1)y2=cos(2*t) + (2*sin(2*t)./9 - cos(2
3、*t).*(sin(3*t)/36 + sin(t)./4 - (t.*cos(3*t)./12 - (t.*cos(t)./4) + sin(2*t).*(cos(3*t)./36 + cos(t)./4 + (t.*sin(3*t)./12 + (t.*sin(t)./4)plot(x,y1,b-,x,y2,r-.)legend(y的图像,y的一阶导图像)2.x=0:2*pi/9:2*pi;y=(sin(2*x).2p3=polyfit(x,y,3);p5=polyfit(x,y,5);p7=polyfit(x,y,7);disp(三阶拟合函数),f3=poly2str(p3,x)disp
4、(五阶拟合函数),f5=poly2str(p5,x)disp(七阶拟合函数),f7=poly2str(p7,x)x1=0:pi/50:2*pi;y3=polyval(p3,x1);y5=polyval(p5,x1);y7=polyval(p7,x1);plot(x,y,rp,x1,y3,-,x1,y5,k-,x1,y7,-);legend(拟合点,三阶拟合,五阶拟合,七阶拟合)第3张1.t1=-pi:pi/4:pi;x1=cos(t1);y1=sin(t1);z1=t1;subplot(1,2,1),plot3(x1,y1,z1)t2=-4:0.25:4x2,y2=meshgrid(t2);z
5、2=sin(x2+y2);subplot(1,2,2),surf(x2,y2,z2),title(sin(x+y)2.functionxdot=exf(t,x)u=0;xdot=0 1;-17/4 -1*x+0 0*u;clf,t0=0;tf=8;x0t=-1;2;t,x=ode23(exf,t0,tf,x0t)y1=x(:,1)y2=x(:,2)plot(t,y1,b-,t,y2,r-.)legend(y的图像,y的一阶导图像)第4张1、figure(1)x,y=meshgrid(-2:.5:2); z=x.2+y.2+3; x1,y1=meshgrid(-2:.1:2); z1=x1.2+
6、y1.2+3; subplot(1,2,1),mesh(x,y,z),title(数据点) subplot(1,2,2),mesh(x1,y1,z1),title(函数图象) xi,yi=meshgrid(-2:.125:2); zi1=interp2(x,y,z,xi,yi,*nearest); zi2=interp2(x,y,z,xi,yi,*linear); zi3=interp2(x,y,z,xi,yi,*spline); zi4=interp2(x,y,z,xi,yi,*cubic);figure(2) subplot(221),mesh(xi,yi,zi1),title(最近点插值
7、) subplot(222),mesh(xi,yi,zi2),title(线性插值) subplot(223),mesh(xi,yi,zi3),title(样条插值) subplot(224),mesh(xi,yi,zi4),title(立方插值) 2、functionxdot=exf(t,x) u=t; xdot=0 1;-2,2*x+0 1*u; t0=0; tf=4; x0t=1;pi; t,x=ode23(exf,t0,tf,x0t); y1=x(:,1); y2=x(:,2); plot(t,y1,r-,t,y2,b-) legend(y,y一阶导数)第5张1.x=-5:0.01:0
8、;y=3.*exp(sin(x).*cos(x)+x.(-2);plot(x,y,r.)holdonx=0:0.01:5;y=3.*exp(sin(x).*cos(x)+x.(-2);plot(x,y,g.)2.functionxdot=exf(t,x)u=t.*tan(t);xdot=01;-40*x+01*u;clf,t0=0;tf=10;x0t=1;2;t,x=ode23(exf,t0,tf,x0t)y1=x(:,1),y2=x(:,2);plot(t,y1,-,t,y2,o)第6张1.t=0:pi/50:2*pi;x=2*cos(t);y=2*sin(t);subplot(1,1,1)
9、,plot(x,y,b-)2.functionxdot=exf(t,x)u=1-t2;xdot=0 1;0 t*x+0 1*u;clft0=0;tf=2;x0t=0.1;0.2;t,x=ode23(exf,t0,tf,x0t)y1=x(:,1),y2=x(:,2);plot(t,y1,r.,t,y2,b-)第7张1.t1=-8:0.1:8;x1,y1=meshgrid(t1);z1=x1.2/16-y1.2/9;subplot(1,2,1),mesh(x1,y1,z1)t2=0:pi/50:2.*pi;x2=3*cos(t2);y2=2*sin(t2);subplot(1,2,2),plot(x2,y2)2.for n=1:40p0(n)=prod(100:-1:100-n+1)/100n;p1(n)=1-p0(n);endn=1:40;plot(n,p0,n,p1,-)xlabel(人数),ylabel(概率)legend(房间各不同的概率,至少两人相同的概率)axis(0 40 -0.1 1.1),grid on
