not enough input arguments help in line 6 please explain why.

ic = [2.5;0;0;0]; vspan = [0 10];
%[v,x] = ode45(@(v,x)ch6(t,x),vspan,ic);
[v,x] = ode45(@ch6,vspan,ic);
plot(v,x)

function xdot=ch6(v,x)

k = 0.0443;
Cto = 0.3045;
Fao = 2.5;
Ft = x(1)+x(2)+x(3);  %%not enough input arguments
Ca = Cto*x(1)/Ft;
ra = -k*Ca;
rb = -ra;
rc = -2*ra;

xdot(1,:) = ra;
xdot(2,:) = rb;
xdot(3,:) = rc;
xdot(4,:) = 1-x(1)/Fao;

end

Answer 1

[Torsten]

Works (see above).

The list of input arguments to your function in the call to ode45 was wrong.

[v,x] = ode45(@(v,x)ch6(t,x),vspan,ic);

makes no sense since t is undefined.