MATLAB 程式設計 Learning Arrays and x-y

Plotting

方煒 台大生機系

MATLAB 程式設計

Ex4_2 xy Plots, Labels, and Titles

dx=.01; x=.5*dx:dx:10-0.5*dx; y=sin(5*x); plot(x,y,’r-’);

nhalf=ceil(length(x)/2); plot(x(1:nhalf),y(1:nhalf),’b-’) plot(x(nhalf:end),y(nhalf:end),’b-’)

xlabel(’\theta’) ylabel(’F(\theta)’) title(’F(\theta)=sin(5 \theta)’)

s=sprintf(’F(\\theta)=sin(%i \\theta)’,5) title(s)

MATLAB 程式設計

Ex4_3 Overlaying Plots

close y2=cos(x); % the second function % plot both plot(x,y,’r-’,x,y2,’b-’)

close all; plot(x,y,’r-’) hold on plot(x,y2,’b-’) Hold off

MATLAB 程式設計

Ex4_4 xyz Plots: Curves in 3-D Space

clear;close all; dphi=pi/100; % set the spacing in azimuthal angle N=30; % set the number of azimuthal trips phi=0:dphi:N*2*pi; theta=phi/N/2; % go from north to south once r=1; % sphere of radius 1 % convert spherical to Cartesian x=r*sin(theta).*cos(phi); y=r*sin(theta).*sin(phi); z=r*cos(theta); % plot the spiral plot3(x,y,z,’b-’) axis equal

MATLAB 程式設計

Ex4_5 Logarithmic Plots

x=0:.1:8; y=exp(x); semilogx(x,y); title(’Semilogx’) pause semilogy(x,y); title(’Semilogy’) pause loglog(x,y); title(’Loglog’)

MATLAB 程式設計

Ex4_6 Generating Multiple Plots

x=0:.01:20; f1=sin(x); f2=cos(x)./(1+x.^2); figure plot(x,f1) figure plot(x,f2)

MATLAB 程式設計

Ex4_7 Controlling the Axes

close all; x=.01:.01:20; y=cos(x)./x; plot(x,y) axis([0 25 -5 5])

plot(x,y) xlim([ 0 25])

plot(x,y) ylim([-5 5])

axis equal

MATLAB 程式設計

Ex4_8 Greek Letters, Subscripts, and Superscripts

\alpha \beta \gamma \delta \epsilon \phi \theta \kappa \lambda \mu \nu \pi \rho \sigma \tau \xi \zeta

Θ1 is coded with \theta_1 Θ12 is coded with \theta {12} Θ10

is coded with \theta ^{10} text(10,.5,’Hi’);