(VAR x y)
(RULES
D(t()) -> 1
D(constant()) -> 0
D(+(x,y)) -> +(D(x),D(y))
D(*(x,y)) -> +(*(y,D(x)) , *(x,D(y)))
D(-(x,y)) -> -(D(x),D(y))
D(minus(x)) -> minus(D(x))
D(div(x,y)) -> -(div(D(x),y) , div(*(x,D(y)),pow(y,2)))
D(ln(x)) -> div(D(x),x)
D(pow(x,y)) -> +(*(*(y,pow(x,-(y,1))),D(x)) , *(*(pow(x,y),ln(x)),D(y)))
)
(COMMENT Example 11 in \cite{D33})