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## Main Question or Discussion Point

Dear all. I am trying to solve an ODE in MATLAB using ODE45 solver. But the programe keep saying

??? Input argument "y" is undefined.

Error in ==> lvv at 4

yprime=[a*y(1)-b*y(1)*y(2);-r*y(2)+c*y(1)*y(2)];

Can anybody be of help? Please.

The complete code is this:

function yprime=lvv(t,y)

%LV: Contains Lotka-Volterra equations

a=.5471;b=.0281;c=.0266;r=.8439;

yprime=[a*y(1)-b*y(1)*y(2);-r*y(2)+c*y(1)*y(2)];

[t,y]=ode45(@lvv,[0 20],[30;4])

plot(t,y(:,1))

Thanks

??? Input argument "y" is undefined.

Error in ==> lvv at 4

yprime=[a*y(1)-b*y(1)*y(2);-r*y(2)+c*y(1)*y(2)];

Can anybody be of help? Please.

The complete code is this:

function yprime=lvv(t,y)

%LV: Contains Lotka-Volterra equations

a=.5471;b=.0281;c=.0266;r=.8439;

yprime=[a*y(1)-b*y(1)*y(2);-r*y(2)+c*y(1)*y(2)];

[t,y]=ode45(@lvv,[0 20],[30;4])

plot(t,y(:,1))

Thanks