Aron Y. answered 06/08/19
Used Mathematica extensively since 2003, for scientific and genl. work
Yes, you can reuse any output in Mathematica. There are many ways to do this, but the simplest is to assign the output to a variable. Then anytime you call the variable, you get that output. For instance:
d = D[x^2, x]
=> 2 x
d
=> 2 x
For more information, go to the Mathematica documentation and search for "defining variables".