Thanks for the replies, any more thoughts so I can show him this thread? If there's no official rule about making a common denominator I'm going to talk to her about this again (I tried once already T.T).
The only solid thing I can say is that taking the derivative of my form is easier, and...
you forgot the part where the fraction here DOESNT become simplified when you combine the fraction.. in fact it becomes complified therefore i don't see a reason to do this. there was another question where taking the common denom canceled out some stuff but here it did nothing so i didn't do it..
I don't know if this is calculus or not but this was on a calculus test. It was the last step of a third derivative question. I lost a mark because the teacher says (x^2-1)/x^2 is more simplified than 1-(1/x^2).. is this fair? Is there an official rule that states (x^2-1)/x^2 is more simplified...