Question

帮忙做几个简单的MATLAB题目

Answer 1

clc;clear;close all

theta=[0:0.1:2*pi];

x=theta;

%9条曲线画一起你不嫌乱啊?

%问题1

for i=1:9

figure(1);

hold on;

y1=cos(((i-1)*2+1)*theta);

plot(theta,y1,'color',[rand(1),rand(1),rand(1)]);

axis equal

end

xlabel('x');

ylabel('y');

%问题2

X=[0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1];

Y=[3 1 8 16 12 18 23 27 30 13];

order=[3 5 8];

colorctrl={'r','g','b'};

for i=1:3

poly=polyfit(X,Y,order(i));

Yf=polyval(poly,X);

figure(2);

hold on

plot(X,Yf,colorctrl{i});

end

figure(2);plot(X,Y,'rs');

legend('3阶','5阶','8阶','原始数据',2);

xlabel('x');

ylabel('y');

%problem 3

%你的表达式不是标准的,不知道你要表达什么,我先按我理解的做了,不对的话你自己改下

y1=0.2-0.5*x.*cos(4*pi*x);

y2=2-0.5*x.*cos(pi*x);

figure(3);

plot(x,y1,x,y2);

legend('y1','y2');

xlabel('x');

ylabel('y');

%problem 4

%不知道你说的绕Z轴旋转两遍是什么意思,是不是我弄的这样

figure(4)

x=[-3:0.1:3];

y=x;

[Xi,Yi]=meshgrid(x,y);

Zi=-sin(Xi).^2-cos(Yi).^3;

surf(Xi,Yi,Zi);

xlabel('x');

ylabel('y');

zlabel('z');

for i=1:180;

figure(4);

pause(0.01);

view(i,30);

axis equal

end

view(-37.5,30)