Legend in a loop for two graphs

Question

ikram ros salamat 2021-3-5

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/764206-legend-in-a-loop-for-two-graphs

评论： ikram ros salamat 2021-3-5

Hello,

So I have a code for two plots but one of the plot changes with each loop. I want to be able to write down the legend which shows the value that makes the plot change. So far I have this code, however when I run it, my second legend that should show the word 'Signal' get over written by num2str(i).

Thanks.

V = 1; 
x = [0:0.01:15];
y = V*sin(x/2);   % studied function
a0= (4/pi)*V;
n = 3;
sum = 0;
for i=1:n 
    an = 4/(1-4*i^2)*(V/pi);    
    sum = sum + an*cos(i*x);
    f = a0/2 + sum;
    figure();
  
    %% plot 1
    plot(x,f,'LineWidth',1.5); 
    hold on
    
    %% plot 2
    plot(x,abs(V*sin(x/2)),'LineWidth',1.5);
    legend('Expansion for n =',num2str(i),'Signal','location', 'best');
    
    grid minor;
    ylim([0 1.5]);
    hold on
end 

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Answer 1

nines 2021-3-5

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Hello!

Is this what you are trying to do:

if so, here is the code (all I did was some rearranging):

V = 1; 
x = [0:0.01:15];
y = V*sin(x/2);   % studied function
a0= (4/pi)*V;
n = 3;
sum = 0;
for i=1:n 
    an = 4/(1-4*i^2)*(V/pi);    
    sum = sum + an*cos(i*x);
    f = a0/2 + sum;
    figure();
  
    %% plot 1
    plot(x,f,'LineWidth',1.5); 
    hold on
    
    %% plot 2
    plot(x,abs(V*sin(x/2)),'LineWidth',1.5); hold on
    legend(['Expansion for n =' num2str(i)],'Signal','location', 'best');
    
    grid minor;
    ylim([0 1.5]);
    hold on
end 