Missing plot line and legend mismatch

Question

Linee Teh 2019-10-9

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/484307-missing-plot-line-and-legend-mismatch

评论： Star Strider 2020-1-31

My coding is as follow and the result shown only 2 lines are plotted with the same colour. Also, the legend mismatched with the plotting line. May I know what are the things went wrong in this coding?

% Initial condition & parameters

u = 7.9e15; % Wbm

a = 6.90633e6; % m

w0 = 0.0011; % rad/s

im = 51.6*pi/180; % rad

t= [0:2000];

% Magnetic field

Bx = (u/a^3)*cos(w0*t)*sin(im);

By = -(u/a^3)*cos(im);

Bz = 2*(u/a^3)*sin(w0*t)*sin(im);

% subplot(3,2,3)

figure (3)

plot(t, Bx, t, By, t, Bz)

title('Graph of magnetic field vs time')

xlabel('Time,t(s)')

ylabel('Magnetic field, b (Tesla)')

legend('Bx','By','Bz')

grid

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Answer 1

Star Strider 2019-10-9

1
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/484307-missing-plot-line-and-legend-mismatch#answer_395426

在 MATLAB Online 中打开

Note that ‘By’ is a scalar, so it actually will not appear on the plot (unless you plot it with a marker). They will all plot as they should if you multiply ‘By’ by a ones vector:

%  subplot(3,2,3)
 figure (3)
 plot(t, Bx,  t, By*ones(size(t)),  t, Bz)
 title('Graph of magnetic field vs time')
 xlabel('Time,t(s)')
 ylabel('Magnetic field, b (Tesla)')
 legend('Bx','By','Bz')