Use whatever form you are used to- it really doesn't matter whether you call it " " or " " or call the function by any other name. A function by any other name differentiates as good!
hi, a question asks "find the derivatives with respect to x of the following"
they are given in a form without y. e.g -3sin(3x) or 1/(3e^(3x))
can i assume them to be y= .... e.g y=-3sin(3x) when differentiating or must i state: let y=........ and then differentiate that.