% T1

% 最好还是设 h=2 D=1

clear,clc;

h=2;D=1;

x=-2*D:0.01:2*D;

y=h*(x>D)+h/D.*x.*(abs(x)<=D)-h*(x<-D);

% T_2

clear,clc;

%用 cumsum函数

% A = (0:63);

% B = cumsum(2.^A);

% S = B(64)

%用for循环

% clear,clc

% s=0;

% for i=0:63

%     s = s+2.^i;

% end

% s

%用sum函数

clear,clc

sum(2.^[0:63])

% T_3

clear,clc

x1=1;

xn = x1/2+3/2*x1;

y = xn/2+3/2*xn;

disp(abs(y-xn));

while abs(y-xn)>10e-14

    xn = y;

    y = xn/2+3/2*xn;

end

y;

% T_4

clc,clear

x=0; y=0;

for i=1:30000

    x(i+1)=1+y(i)-1.4*x(i)^2;

    y(i+1)=0.3*x(i);

end

%plot(x,y);

plot(x,y,'.');

% T_5   两个脚本文件

% bisect5.m

<pre name="code" class="plain">function [c,err,yc]=bisect5(f,a,b,delta)

%Input - f is the function

% - a and b are the left and right endpoints

% - delta is the tolerance

%Output - c is the zero

% - yc= f(c)

% - err is the error estimate for c

%If f is defined as an M-file function use the @ notation

% call [c,err,yc]=bisect(@f,a,b,delta).

%If f is defined as an anonymous function use the

% call [c,err,yc]=bisect(f,a,b,delta).

ya=f(a);

yb=f(b);

if ya*yb > 0,return,end

max1=1+round((log(b-a)-log(delta))/log(2));

for k=1:max1

c=(a+b)/2;

yc=f(c);

if yc==0

a=c;

b=c;

elseif yb*yc>0

b=c;

yb=yc;

else

a=c;

ya=yc;

end

if b-a < delta,break,end

end

c=(a+b)/2;

err=abs(b-a);

yc=f(c);

% 1_5.m

<pre name="code" class="plain">clc,clear

format long

[answerr,error,value]=bisect5(@(x)x^2*sin(0.1*x+2)-3,0,1000,1e-8)

% T_6

clc,clear

t=[0,120,240,0]*pi/180; % 变换成弧度

x=[]; y=[];

for i=0:5:360

tt=i*pi/180;

x=[x; cos(tt+t)]; y=[y; sin(tt+t)];

end

plot(x',y','r'), axis('square')

% T_7

clc,clear

f=@(x,y,z)(x.^x+x.*y+x.*z).*exp(-z)+z.*z.*y.*x+sin(x+y+z.*z);%定义函数 f=x^2+y^2+z^2-10

[x,y,z]=meshgrid(linspace(-4,4,25));%设定网格大小和范围

val=f(x,y,z);

[p,v]=isosurface(x,y,z,val,0);%用 isosurface 得到函数 f=0 图形的点和面

patch('faces',p,'vertices',v,'facevertexcdata',jet(size(v,1)),'facecolor','w','edgecolor','flat');%

% 用 patch 绘制三角网格图并设定色彩

view(3);

grid on;

axis equal

% T_8

clc,clear

%  xy的三维图与等高线

% [x,y]=meshgrid(-1:.1:1);

% surf(x,y,x.*y), figure; contour(x,y,x.*y,30)

%sin xy 的三维图与等高线

[x,y]=meshgrid(-pi:.1:pi);

surf(x,y,sin(x.*y)), figure; contour(x,y,sin(x.*y),30)