So a week ago, I was marking a few scripts of my students (Yes about half of them were honing their skills to handle prelim papers now; I hope you are too.) and I noticed a handful can’t tell when to use which formula in the MF15.

They are confused when to differentiate and when they can use the standard series expansion.

As you all should know, the first formula there is the general Maclaurin’s Series, while the remaining five are standard results for common functions. So when do we use what in questions?

I told my students that they need to read the keywords carefully! If questions prompt you to use STANDARD SERIES or SERIES expansion then the remaining five should be used, while maclaurin’s series refer to the first one. Furthermore, questions usually reward us with 1 or 2 marks just to show the second order; this is a hint for you to differentiate (pun intended).