Means the exact same thing, but usually I use loge(x) to avoid the possibility of using copy/paste from CAS (Which sometimes loses marks if CAS syntax is used). 
)
isn't cas syntax,
)
is the proper maths way of writing it (well they're both proper maths ways, I mean in actual maths it's convention to use
)
. With that being said, we've heard that apparently vcaa doesn't like
)
, so it's better to stick with
)
(I'm not sure if you'd actually lose any marks or not if you didn't though).
Really some years they'll be more picker than others. If it is an easy exam, then to separate people they'll be more picky, and if it's a hard exam, they may be a little bit more lax. Before the group of teachers and such that get to go mark the exam, they have a big meeting and agree on how they're going to mark it which can change each year depending on what the head assessor decides.