MATLAB绘图，绘双坐标轴，绘一图二轴等

clc;
clear all;
close all;

% %% 画极坐标系

% x = 0:.01 * pi:0.5 * pi;
% y = cos(x) + sqrt(-1) * sin(x);
% plot(y*2,'r','linewidth',5);
% hold on
% warning('off')
% 
% x = pi * 0.5:0.01:pi;
% y = cos(x) + sqrt(-1) * sin(x);
% plot(y*2,'y','linewidth',5);
% hold on
% warning('off')
% 
% x = pi :0.01:1.5 * pi;
% y = cos(x) + sqrt(-1) * sin(x);
% plot(y*2,'b','linewidth',5);
% hold on
% warning('off')
% 
% x = 1.5 * pi :0.01:2 * pi;
% y = cos(x) + sqrt(-1) * sin(x);
% plot(y*2,'g','linewidth',5);
% hold on
% warning('off')
% 
% title('极坐标系');
% text([1.5,-3,1.5,-3],[2,2,-2,-2],{'第一象限','第二象限','第三象限','第四象限'});
% legend({'[0 0.5\pi]','[0.5\pi \pi]','[\pi 1.5\pi]','[1.5\pi 2\pi]'});
% xlim([-4,4]);
% ylim([-4,4]);
% 
% plot([-3,3],[0,0],'k','linewidth',4)
% plot([0,0],[-3,3],'k','linewidth',4)
% 
% axis off
% %% 画双轴坐标（1）

% figure
% ang1 = 0:.01*pi:2*pi;
% amp1 = sin(0:.01*pi:2*pi);
% z = amp1 .*(cos(ang1) + sqrt(-1) *sin(ang1));
% [Ax,H1,H2] = plotyy(0:200,abs(z),0:200,angle(z) * 180/pi);
% set(get(Ax(1),'ylabel'),'string','sfsdf');
% set(get(Ax(2),'ylabel'),'string','dsfsdffd');
% set(H1,'linewidth',3)
% set(H2,'linestyle',':','linewidth',3)

%% 一图多轴

x1 = (0:.1:40);
y1 = 4 .* cos(x1) ./ (x1 + 2);
mag = magic(20);
x2 = (1:.2:20);
y2 = x2.^2./x2.^3;
%显示第一个坐标轴对象
h11 = line(x1,y1,'color','r','linewidth',2);
ax1 = gca;
set(ax1,'linewidth',2);
%添加第二个坐标轴对象
A = get(ax1,'position');%获取ax1的位置，为[left，bottom，width，height]
A(1:2) = A(1:2) + 0.1;
A(3:end) = A(3:end) - 0.2;
ax2 = axes('position',A,...
           'xAxisLocation','bottom',...
           'yAxisLocation','left',...
           'Color','none',...
           'xColor','k','yColor','k');
 %注意这里如果用plot函数，将会产生图像覆盖，应为line是产生几何图像
 h12 = line(x2,y2,'color','k','parent',ax2,'linewidth',2);
 h12 = line(x2,y2+0.1,'color','k','parent',ax2,'linewidth',2);
 set(ax2,'linewidth',2);
 box off
 xlim([0,20]);
 ylim([0,2]);
%  xlimitsl = get(ax1,'xlim')