MATLAB R2010a

x=1:6;

Y=[170 120 180 200 190 220; 120 100 110 180 170 180; 70 50 80 100 95 120]

bar(x,Y','style');

% bar(x,Y','grouped'); % bar(x,Y','stacked'); colormap(cool);

% legend('A','B','C','Location','NorthWest') legend('A','B','C',2)

%习题5_4 % exmp504.m 供第4道习题使用的程序

clc,clf,clear; t=(0:0.05:18)'; N=length(t);

zeta=0.2:0.2:1.4; L=length(zeta); y=zeros(N,L); hold on for k=1:L

zk=zeta(k);

beta=sqrt(abs(1-zk^2)); if zk<1 缺陷在此，由于计算机的精度，zeta(5)<1 ,可改为zk-1<-2*eps %满足此条件，绘蓝色线 y=1/beta*exp(-zk*t).*sin(beta*t); plot(t,y,'b') if zk<0.4

text(2.2,0.63,'\\zeta = 0.2') end elseif zk==1 缺陷在此，由于计算机的精度，zk！=1 ,可改为(zk-1)<2*eps%满足此条件，绘黑色线 y=t.*exp(-t);

plot(t,y,'k','LineWidth',2) else %其余，绘红色线

y=(exp(-(zk-beta)*t)-exp(-(zk+beta)*t))/(2*beta); plot(t,y,'r') if zk>1.2

text(0.3,0.14,'\\zeta = 1.4') end end

end

text(10,0.7,'\\Delta\\zeta=0.2') axis([0,18,-0.4,0.8]) hold off box on grid on

%习题5_5

t=4*pi*(0:100)/100; x=sin(t);y=cos(t);z=t;

plot3(x,y,z,'g','LineWidth',3),box on

%习题5_6

x=-3:0.1:3;y=x;[X,Y]=meshgrid(x,y); Z=4.*X.*exp(-X.^2-Y.^2); mesh(X,Y,Z) hidden off

% colormap(cool), % shading interp,

syms x y z

% z=4.*x.*exp(-x.^2-y.^2); z=4*x*exp(-x^2-y^2); ezmesh(z,[-3,3]) hidden off

%习题5_7 clear all

x=4*pi*(-50:50)/50;y=x;[X,Y]=meshgrid(x,y); Z=sin(X+Y)./(X+Y+(X+Y==0)*eps); surf(X,Y,Z)

view([21,32]) %图形界面旋转图形，认为合适后记下方位角和俯视角，再写出命令

shading interp

% size(find(isnan(Z))) % sum(sum(isnan(Z)))

%习题5_8

ezplot('y/(1+x^2+y^2)-0.1',[-2*pi,2*pi,-pi/3,3.5*pi]) hold on

ezplot('sin(x+cos(y))',[-2*pi,2*pi,-pi/3,3.5*pi])

可看到6个交点，及方程组有6个实数解

要解最接近x=0,y=0的解，首先将‘myfun8’另存为一个文件 function F=myfun8(x,y)

F=[y/(1+x^2+y^2)-0.1;sin(x+cos(y))] end

zoom on

xy= ginput(1)

f=fsolve(@myfun8,xy)

[X,Y] = ginput(1)

f=fsolve(@myfun8,[X,Y])

clear all syms x y

s=solve('y/(1+x^2+y^2)-0.1','sin(x+cos(y))') 在2010版求解即得最接近x=0,y=0的解，

%习题5_9

在6.5版本无法运行%习题5_9 function f=prob5_9 clf;

[X,Y,Z]=sphere(40);

surf(X,Y,Z),axis equal off,shading flat set(gcf,'Color','w') material shiny

light('position',[-1,0.5,1]) light('position',[2,1,1]) colormap([jet; flipud(jet)])

disp('按任意键，观察色图变幻。退出按Ctrl+C') pause

spinmap(80,9)

%习题5_10p

function f=prob5_10(K,ki)

%prob5_10函数产生动态衰减正弦函数，K控制动态曲线动态变化的循环次数，ki控制曲线动态变化的快慢 nargin=0 clf

t=0;k=0;

x=(0:100)/100*4*pi; n=length(x); y0=zeros(n);

plot(x,y0,'b','LineWidth',2.5);hold on

plot(x(1),y0(1),'d','MarkerFace',[0,0,1]); axis off; if nargin==0 K=1;ki=1;

elseif nargin==1 ki=1; end

while 1 t=t+1;

y1=sin(pi*t/24); y(2:n)=y0(1:n-1); y(1)=y1; y0=y;

y=exp(-0.2.*x).*y;

plot(x,y,'LineWidth',2.5);hold on

plot(x(1),y(1),'p','MarkerSize',20,'MarkerFace',[0,0,1]);hold off axis([ 0 14 -1.2 1.2]) axis off;

if round(t/240)==K break end

pause(0.001*ki) end

f=getframe(gcf)

%习题5_10p,用line函数

function f=prob5_10(K,ki)

%prob5_10函数产生动态衰减正弦函数，K控制动态曲线动态变化的循环次数，ki控制曲线动态变化的快慢 nargin=0 clf

t=0;k=0;

x=(0:100)/100*4*pi; n=length(x); y0=zeros(n);

h1=line(x(1),y0(1),'Marker',

'd','MarkerSize',20,'MarkerFace',[0,0,1]); h=line(x,y0,'LineWidth',2.5,'Color',[0 0 1]);