Error using odearguments (line 113) Inputs must be floats, namely single or double.

Error using odearguments (line 113)

Inputs must be floats, namely single or double.

Error in ode45 (line 115)

odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);

Error in Untitled3 (line 6)

[t,y] = ode45(@(t,y)dynamics(t,y), tspan, y0)

The function is

function dydx = dynamics(x,y)

dydx = [ y(2); -0.3*y(2)+ y(1)-(y(1))^3+ 0.2*cos(5.2360*t)];

The code is

syms t

u=1.2;

T=2*pi/u;

tspan = [0 300*T];

y0 = [0; 0];

[t,y] = ode45(@(t,y)dynamics(t,y), tspan, y0)

Please let me know how to solve this issue.

Answer 1

[Daniel M]

Your function dynamics takes as inputs x and y, but instead uses t and y. So fix that.

You are also passing in a symbolic value for t. So just delete the line

syms t

Otherwise, if you would like to solve this ode symbolically, I suggest reading the existing doc on how to do so:

https://www.mathworks.com/help/symbolic/solve-a-single-differential-equation.html

(But actually, I do not get an error running it with 'syms t' once the function dynamics is fixed. Version R2019a).