Unexpected output when trying to plot the solution to a system of nonlinear differential equations

1 view (last 30 days)
The following Matlab code is meant to plot x(1) vs time and x(2) vs time separately, but only plots x(1) vs time. Despite there being two lines of code to generate each plot, one line is ignored. Does anyone have any suggestions as to how the code can be modified?
t = [0 10]; %time interval ranges from 0 to 10 s
ic = [pi/3; 0; 0; 0]; % initial conditions = [θ θ' x x']
[t,x] = ode45(ode, t, ic);
plot(t,x(:,1), 'o') %the y axis represents
plot( t,x(:,2),'o') %the y axis represents
xlabel('x(m)');
ylabel('θ(rad)');
function dydx = fun(t,x)
%[x(1) x(2) x(3) x(4)] = [angle angular velocity x position x velocity] respectively
L = 0.5; g = 9.81;
dydx = zeros(4,1);
dydx(1) = x(2);
dydx(2) = (4*sin(x(1))*(5*L*cos(x(1))*x(2)^2 + 6*g))/(L*(20*cos(x(1))^2 - 23));
dydx(3) = x(4);
dydx(4) = -(5*sin(x(1))*(23*L*x(2)^2 + 24*g*cos(x(1))))/(6*(20*cos(x(1))^2 - 23));
end

Accepted Answer

Torsten
Torsten on 4 Apr 2020
Use
hold on
between the two plot commands.

More Answers (0)

Categories

Find more on Systems of Nonlinear Equations 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!