(no subject)

[mariana]

I am going to fail my FP3 exam... there is no doubt of this. I have been revising all day, I can't do complex numbers and I only just finished matrices. I still have three chapters to go, including vectors (which is going to take me decades) and I don't understand anything I've done yet.

Good thing is - my brain has died, so I'm not even going to notice failing. Bad thing is I'm not sure it's going to recover before Monday, when I have my last exams, which are together, synoptic and Chemistry and therefore a bitch.

I should get back to it, but my headache just won't go away and I keep staring at the page like it's the television screen, as though it's just going to talk me through my revision, which would be wonderful, but alas, has yet to be done properly.

An interactive revision page thingy. That would be cool.

Can anyone teach me complex numbers in the next half hour?

Comments

[chottochigamats.livejournal.com]

www.mathsnet.net might be some help
www.thestudentroom.co.uk has a nice maths forum

Complex numbers:
re^i@ = r(cos@ + isin@)

Useful thing is the expansion of, say, cos5@
(cos5@ + isin5@) = r^5(cos@ + isin@)^5 from de Moivre's theorem, but r=1
= (cos@ + isin@)^5
Then expand using the Binomial Theorem and take only the real elements, as we only want cos@ (you'll need to use sin@^2 = 1 - cos@^2)

Elementary (why call it that? It just makes me feel dumb) transformations from the z to the w planes:
Try to write z in terms of w, then apply the transformations to z necessary to use the identity you've been given, e.g. |z| = 1

Argand Diagram geometry stuff (most of these are fairly obvious given a bit of thinking, alternatively, convert z to x+iy, then demodulusify (good word) both sides):

|z+p+qi| = x : circle of radius x, centre (p,q)
|z+p| = |z+qi| : line bisecting the two points. not sure how to write this down

if any others turn up, convert to x+iy

sinh z = i sin z (I think)
cosh z = cosi z (again, check these)

I hope that's it. Vectors is hell.

[mariana-oconnor.livejournal.com]

Wow... thank you - might have been more helpful had I read this before the exam, but meh, I'll take what I can get.

It actually makes sense, and luckily the complex number questions were reasonable. (thank GOD!) The vectors sucked, because it was the bit I didn't get a chance to revise - not that I would have done any better had it been, but I might have written something down.

How did you find it? Don't make me feel too stupid please... well, you can if you want.

Coming to Claire's this afternoon? Are you sitting Biology right now? I know that's a stupid question, but it sort of makes sense, in that if I get a reply you probably aren't and if I don't you might be.

If you do come I'll see you then, if you don't we need to organise some time for me to give you back your DVD (and PotC comes out on 6th July -yay!)

Thanks.

[rachey-me-matey.livejournal.com]

lol wow that must have taken a while to write! What do you reckon about the fp3 exam? ooh and have you looked at the Warwick accomodation yet?

[just-spud.livejournal.com]

Uh, wow. Something tells me you would have been better at teaching us that stuff than our actual teachers! How did you find the exam? I messed up the loci complex numbers questions... and the vectors. In fact, the more I think about it, the more I realise what I did wrong.

[chottochigamats.livejournal.com]

I doubt I could teach it well, I'd get confused and go off on tangents, that's my problem. The exam was ok, but not great. I know I lost a decent number of marks, so I'm not tthinking about it. Are you partying on friday?