**Defined in theory: Unary-scalar-functions****Source code: unary-scalar-functions.lisp**

**Documentation:**(D/DT ?q) is the derivative with respect to time of the

time-dependent-quantity ?q. It is undefined on other quantities, including constant-quantities.**Arity:**2

(=> (D/Dt ?Q ?Time-Derivative) (And (Time-Dependent-Quantity ?Q) (= ?Time-Derivative (Deriv ?Q))))