Motor torque x speed curve – behavior at 0 rpm

Hello all, this is my first post. I'm a mechanical engineer working with rotating equipment.
 

I'm designing hardware and software to implement IEE Std 112 7.3.2.2 method (acceleration) to get the torque/speed curve of electric motors.

Is there a theoretical value for the *derivative* of torque in relation to speed at 0 rpm? Specifically, is it zero?

Thanks.