ทำไมรันในMaple13ไม่ออก

[hihihi]

คือผมอยากจะแทนค่าตัวเลขลงในสมการและผมอยากจะยุบรวมสมการให้เป็นสมการเดียวhttp://image.ohozaa.com/view/84t6j
รุปนี่อะครับ
http://image.ohozaa.com/view/84t6j

[hihihi]

> assume(A > 0);
> assume(B > 0);
> assume(c > 0);
> assume(alpha > 0);
> assume(beta < 0);
> assume(0 < h and h < 1);
> assume(sigma = 0.5e-1);
> phi := proc (Y) options operator, arrow; A/(1+e^(-BY))-(1/2)*A end proc;
A 1
Y -> ---------- - - A
(-BY) 2
1 + e
> Typesetting:-Parse:-ConvertTo1D, "first argument to _Inert_ASSIGN must be assignable";
Error, illegal use of an object as a name
Typesetting:-mambiguous(IAssignYcommaKrarr&phi;ApplyFunction(Y) + &beta;sdotK,

Typesetting:-merror("illegal use of an object as a name"))
>
> DEplot([phi(Y)], A = 0 .. 4, B = 0 .. 1, arrows = medium);
Error, (in DEtools/DEplot) vars must be declared as a list, e.g. [x(t),y(t),...]
> (D(Y))(t) = alpha[(I)(Y(t), K(t))-S(Y(t))];
A
alpha[---------- + beta K - gamma Y] = alpha[I - gamma Y]
(-BY)
1 + e
> (D(K))(t) = (I)(Y(t-theta).K(t))-`&delta;K`(t);
D(K)(t) = I - &delta;K(t)
> S(Y(t)) := gamma*Y;
> (D(Y))(t) := alpha[A/(1+e^(-BY))+beta*K-gamma*Y];