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From: trung trinh on 18 Apr 2010 12:49
function vdp
syms t;
f = sin(t)*cos(t)*exp(-100*t); % This is an example function. Our function maybe more complex than it.
tspam = [0 12];
x0 = [0 1]';
[t, x] = ode45(@vdpp, tspam, x0, [], f);
plot(t,x(:, 1)); grid on;
function dxdt = vdpp(t, x,f)
dxdt = [x(1); x(2)+f];

Dont work. Help me
From: Torsten Hennig on 18 Apr 2010 22:40
> tspan = [0 12];
> x0 = [0 1]';
> [t, x] = ode45(@vdpp, tspan, x0, []);
> plot(t,x(:, 1)); grid on;
> function dxdt = vdpp(t, x)
> dxdt = [x(1); x(2)+sin(t)*cos(t)*exp(-100*t)];
>

Best wishes
Torsten.
From: Steven Lord on 19 Apr 2010 11:43

"trung trinh" <trungkstn(a)gmail.com> wrote in message
news:hqfd60$o0k$1(a)fred.mathworks.com...
> function vdp
> syms t;
> f = sin(t)*cos(t)*exp(-100*t); % This is an example function. Our
> function maybe more complex than it.
> tspam = [0 12];
> x0 = [0 1]';
> [t, x] = ode45(@vdpp, tspam, x0, [], f);
> plot(t,x(:, 1)); grid on;
> function dxdt = vdpp(t, x,f)
> dxdt = [x(1); x(2)+f];
>
> Dont work. Help me

DO NOT mix ODE45 and symbolic expressions; if you want to solve a system
symbolically use DSOLVE, if you want to solve it numerically use ODE45 (or
use SUBS to evaluate the symbolic expression to return a numeric result.)

--
Steve Lord
slord(a)mathworks.com
comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ.


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