Consider the simple function
f(x)=x^2-3/x+ln(x)-.01*x^5
now differentiate it (by the way being able to differentaite a function by name is pretty damn good, well done)
The result is ugly. What we need to be able to do is click on it and simplify it. We can't.
In fact we need to be able to pick up the result and use it elsewhere.