maths... does shortcuts lose marks?

declan_lgs

for example, doing the ratio test I've always always just gotten right into the lim n->infinity |u[n+1] * (u[n] upside down)|
and for easy infinite limits I don't write down that I'm dividing by the highest power and just bung the highest power coefficients into an answer.

Does this be penalised? I mean the examiner will know what I'm doing usually, I know what I'm doing, and I would usually have time to check the answer to be sure.

The only question I intend to be really really verbose for is probability (and proofs is important too I suppose) . . . would I do better to make this policy for all Qs?

edit: also, should I simply use the output of my calc "50 root 2" instead of breaking down sqrt(5000) to sqrt(2500 times 2) and bringing the 2500 out or is that a bad act?

starkinter

The "marks will be lost if all necessary work is not shown" has always confused me. If you don't have to do the work to get your answer, then of course it isn't necessary. At least that's what I'd think is generally meant by 'necessary'.

I'd say this is one of those unfortunate cases where it varies from examiner to examiner, and unless time is a considerable constraint for you, erring on the side of caution is probably the best way of doing things.

What I'd usually do for a root like that is:
√5000
= 50√2
something of a happy medium between your two choices.

who's yer one?

you're safer to just put every single step down, show exactly how you got to yr answer- pretty much write down every little thing that goes through yr head. (math-wise :pac:)
good luck to all!

xxx

declan_lgs

Yeah, I guess ye are right.

If I'm short for time I'll start knockin numbers.

thanks

Fuascailt

It would only hurt you if you made a mistake, like you might make a slip, they cant see your work and think its a blunder, you down two marks. And they all add up! But if you reckon you're ok, you dont need them