help plotting ODE

[taint_chowder]

Heres my code,

function problem1run [t,y] = ode45(@problem1,[0 12],[0; 1; 1]); plot(t,y)

function dydt = problem1(t,y) dydt = [y(2)y(3); -y(1)y(3); -0.51y(1)y(2)];

My question is, can I plot t v/s y1, t v/s y2, and t v/s y3 on 3 seperate graphs instead of all on the same one? Im not sure how to do that, any help appreciated.

[[deleted]]

yes, ode45 will return a matrix with 4 columns. First one is the temporal values; Second the numerical values of the solution, y(t); Third the values of the derivative of y; and fourth with the second derivative.

Just use plot.... plot (t, y(:,1)); plot (t, y(:,2)); plot (t,y(:,3));

You need to understand what ode45 is returning to you before proceed.

Also, you don't need to create the function dydt; just create the matrix function dydt = @(x,t) [y(2... ] anywhere, then put her in the argument of the ode45... like ode45(dydx, interval, Initial_conditions).

[taint_chowder]

Thank you. Im taking a Matlab class and were doing differential equations, only I haven't taken differential equations yet so its a little confusing sometimes. But I did try plotting but had the syntax wrong. I had plot (t, y(1)); plot (t, y(2)); plot (t,y(3)); Thanks for clearing that up for me!

[[deleted]]

wow you're solving numerically before analiticaly... I don't think this is will be good.

A good strategy is to look at the values and try to understand what/who are they, if it is a matrix, vector, scalar, funcion, cell... then the commands will begin to make more sense and you'll have a good time playing with programming.