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How to plot a function with different values

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Raz Omar
Raz Omar on 24 Nov 2019
Commented: TADA on 29 Oct 2020 at 12:46
(M)/1+.5*exp(-k*M*t)*(M-2)
this is the funtuion I want to plot with diffrent M values M= [1,3,5]
clear all
M= 1;
k=0.1;
t=[0:24];
SS= (M)/1+.5*exp(-k*M*t)*(M-2);
plot(SS,'r-');
xlabel('Time IN [SEC]');
ylabel('S');
title('S vs Time')
legend('M1');
I only managed to plot it once with M1
how can I plot it it with 3 lines in one plot command ?

  1 Comment

Rik
Rik on 24 Nov 2019
Have you read the documentation for plot? It contains examples of how you van plot multiple lines at the same time. Your label is also incorrect: you aren't actually plotting against time, you're plotting against the element index.

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Accepted Answer

TADA
TADA on 24 Nov 2019
Edited: TADA on 24 Nov 2019
You can make M a column vector, then calculate S as a matrix
then if you plot it against t which is a row vector plot should treat each row of S as a separate series
M= [1;3;5];
k=0.1;
t=[0:24];
SS= (M)/1+.5*exp(-k*M*t).*(M-2);
plot(t, SS, '-');
legend(strcat('M', num2str(M)));
another approach would be to plot in a loop and use hold on:
for M = [1,3,5]
SS = (M)/1+.5*exp(-k*M*t)*(M-2);
plot(t, SS, '-', 'DisplayName', ['M' num2str(M)]);
hold on;
end
hold off;
legend show;

  2 Comments

Ana Venerio
Ana Venerio on 29 Oct 2020 at 2:18
Thank you so much, this was so helpful :)

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More Answers (2)

Pavel Osipov
Pavel Osipov on 24 Nov 2019
Is exp(-k*M*t)*(M-2) matrix multiplication? Or exp(-k*M*t)*(M-2) element by element?
If element by element:
clear all
M = [1;3;5];%3x1 double
k=0.1;
t=0:24;%1x25 double
Wrk=M.*t;%3x25 double
Wrk1=exp(-k*Wrk);%3x25 double
Wrk2=M+0.5*Wrk1;%3x25 double
M2=M-2;%3x1 double
MM2=repmat(M2,1,length(t));%3x25 double
SS= Wrk2.*MM2;%[%%3x25 double]x[%3x25 double] element by element
figure('color','w')
plot(t,SS(1,:),'r-',t,SS(2,:),'g-',t,SS(3,:),'b-');
grid on;
xlabel('Time IN [SEC]');
ylabel('S');
title('S vs Time')
legend('M1','M2','M1');Wrk.JPG

  1 Comment

Raz Omar
Raz Omar on 24 Nov 2019
Thnkas for the answer , I think it's not element by element as you said , you have used codes outside of my course , thanks for the new info

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Pavel Osipov
Pavel Osipov on 24 Nov 2019
If M2xWrk2 is matrix mult:
%MyAnswer1.m
%If M2xWrk2 is matrix mult
clear all
M = [1;3;5];%3x1 double
k=0.1;
t=0:24;%1x25 double
Wrk=M.*t;%3x25 double
Wrk1=exp(-k*Wrk);%3x25 double
Wrk2=M+0.5*Wrk1;%3x25 double
M2=M-2;%3x1 double
%If M2xWrk2 is matrix mult
MM2=M2';%3x25 double
% --------------------------------------------------------------------------------------------------------
%[%%1x3 * 3x25 ] double matrix product => "String x Column and Sum"
SS= MM2*Wrk2;
% --------------------------------------------------------------------------------------------------------
figure('color','w')
plot(t,SS,'b-','linewidth',2);
grid on;
xlabel('Time IN [SEC]');
ylabel('S');
title('S vs Time')
legend('M1');
Wrk1.JPG

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