MATLAB: Expression (equation)

equationexpression

Hello, how to define an expression, for example 1-e^(-At) where I can define and change parameters A and t and than figure changes of the curve in a graph.

Thanks

Best Answer

Simplest version I can think of

t=0:0.1:100;             % Time vector
A=0.1;                   % Value of A that you can change
plot(t,1-exp(-A(n)*t))   % Represent it on a figure

If you place the cursor on the value of A you can try several values using the Editor tools (look on the tools of your editor window - 1.0 + ... press those symbols and the script runs with a new value for A)

Just for fun here's a version using subplots

clf
t=0:0.1:10;
A=[0.01 0.1 0 1];
for n=1:4
subplot(2,2,n)
plot(t,1-exp(-A(n)*t))
title(['A=' num2str(A(n))])
end

Related Solutions

MATLAB: EMHPM plot function by multisteps

Hi Jose,

I have used array ‘tp’ and ‘Yp’ to store values of ‘t’ and ‘Y’ respectively for evey time step and used it to make the final plot. Below mentioned is the modified code:

t=0;
T=0;
c=1;
yi0=c;
i=1;
while t<=10
    tp(i)=t; % storing t values 
    yi1=(T/1)*(yi0*-exp(t)*yi0*yi0);
    yi2=(T/2)*(yi1*exp(t)-exp(t)*yi1*yi0);
    yi3=(T/3)*(yi2*exp(t)-exp(t)*yi2*yi1);
    Y=yi0+yi1+yi2+yi3;
    yi0=Y;
    Yp(i)=Y; % storing Y values
    t=t+0.1;
    T=0.1;
    i=i+1;
end
plot(tp,Yp) % plotting all t and Y values
xlabel('t')
ylabel('Y')

Output:

Hope this helps!

MATLAB: How to use a for loop to create new variables

There are many posts that say trying to create numbered variables like that is discouraged, yes.

If you want to put all those plots on the same axes, you can do this without creating the individual variables.

t = 0:0.01:10;
% Tell MATLAB not to clear the axes each time you make a new plot
hold on
for M = [0.1, 1, 3]
    plot(t, exp(-M*t));
end
% Optional: the next time you plot into this axes, the existing lines will be cleared
hold off

Best Answer

Related Solutions

MATLAB: EMHPM plot function by multisteps

MATLAB: How to use a for loop to create new variables

Related Question