Input
X abs(x)
Alternate form assuming x and X are positive
x X
Alternate form assuming x and X are real
sqrt(x^2) X
Root
x = 0
Derivative
d/(dx)(X abs(x)) = (x X)/abs(x)
(assuming a function from reals to reals)
Indefinite integral assuming all variables are real
integral X abs(x) dx = 1/2 x^2 X sgn(x) + constant