Thanks Mr. Hall,
But i don't know if I am wrong but when you showed a derivate, it should be dY/dt so i don't understand but parameters as gama and t shouldn't be in the derivate as you can see as others models.
I hope you could understand,
Hi! I am amateur in mathemathicals growth models but I am doing my graduated work in adjust five differents models in some growth parameters in onion,
[PLAIN]http://img820.imageshack.us/img820/2929/models.png
So my doubt is basically in a derivate for gauss model, i can't derivate this model...