# How to plot a function with different values

264 views (last 30 days)
Raz Omar on 24 Nov 2019
Commented: TADA on 29 Oct 2020
(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 ?
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.

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 CommentsShowHide 1 older comment
Cheers!

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');
Raz Omar on 24 Nov 2019
Edited: 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

Pavel Osipov on 24 Nov 2019
If M2xWrk2 is matrix mult:
%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');

### Categories

Find more on Annotations in Help Center and File Exchange

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by