Maths paper 1

EvM

Monsieur Folie wrote: »

What book do you have? I have "Active Maths 4" and it's in it. Hang out, I'll write it out anyway, to make sure I know it off myself. :P

.

Ah, I have New Concise Project Maths 4 and Im quite sure its not in it . That'd be much appreciated in any case

Undeadfred

Monsieur Folie wrote: »

Apologise again for the quality of the photo but hopefully it's legible. This is how I prove De Moivre's theorem by induction. It's actually not too bad and if you remember the rule for multiplying polar numbers together then it doesn't take long either!

You jumped loads of steps going from the 2nd last line to the last line

wow exuberant

Can financial maths be a 50 marker?

Monsieur Folie

Undeadfred wrote: »

You jumped loads of steps going from the 2nd last line to the last line

Do I need to write it out though, since if you remember the rule for multiplying polar numbers that's all you really need?

Maybe I'll go through the process tomorrow if it comes up though, just to be safe.

Undeadfred

Monsieur Folie wrote: »

Do I need to write it out though, since if you remember the rule for multiplying polar numbers that's all you really need?

Maybe I'll go through the process tomorrow if it comes up though, just to be safe.

That's fine for the modulus, but for the argument you have theta on one side and k(theta) on the other. You cant use multilication of powers for that, you have to use page 14-15 of the tables, unless there's something I'm missing here

Monsieur Folie

Hmm, I'm fairly sure if two numbers are in polar form you can just add those bits if you're multiplying, or subtract them if you are dividing.. I'll look into it now though, thank you for pointing that out.

Slow Show

Where did you get that proof from M.Folie? I can see how it works but I, and I reckon most other people, have a different proof where R isn't included in the formula and you end up having to use a formula in the tables book. Tbh I'd be a bit wary of your proof as the formula given in the tables book is (costheta +isintheta)^n = cosntheta + sinntheta), and I reckon that's where you should be working from not with z's and the like, as I don't think that strictly proves the theorem though I could definitely be mistaken!

EDIT: Thinking it over your way with the modulus is probably fine.

HPMS

Can the proof of de moivre's theorem for n is an element of Z be asked? It says in the book beside the n E N that that make be asked but it doesn't specify if the other one can be??

Undeadfred

Monsieur Folie wrote: »

Hmm, I'm fairly sure if two numbers are in polar form you can just add those bits if you're multiplying, or subtract them if you are dividing.. I'll look into it now though, thank you for pointing that out.

Oh **** yeah sorry you're right God what am I saying.

Btw, the one in my book doesn't have a modulus either and uses page 14-15 of the tables book when multiplying it out

weirdspider

HPMS wrote: »

Can the proof of de moivre's theorem for n is an element of Z be asked? It says in the book beside the n E N that that make be asked but it doesn't specify if the other one can be??

Yup it can be

Undeadfred

You know for the proof of the differentiation rule it says n E No (N underscore o)

What is No? (N underscore o)
Am i right in guessing that its Natural numbers including 0?

HPMS

weirdspider wrote: »

Yup it can be

Thank you!!

Btw, the one in my book does have a modulus...uses the same formula as on page 20 of the tables:

r(cosX + isinX)^n = r^n(cosnX + isinnX)

Is that what you're all talking about?

CookieMonster.x

weirdspider wrote: »

Yup it can be

It says in the syllabus 'prove de moivre's theorem by induction for n E N so unless it's written somewhere else I presume we don't?

HPMS

CookieMonster.x wrote: »

It says in the syllabus 'prove de moivre's theorem by induction for n E N so unless it's written somewhere else I presume we don't?

Oh really? Well then the syllabus must be right! That's a relief cause I really was not looking forward to learning that proof!

aoifemcg94

Please tell me this mainly on about higher maths?
because if not, WHAT :O :L

CookieMonster.x

HPMS wrote: »

Oh really? Well then the syllabus must be right! That's a relief cause I really was not looking forward to learning that proof!

Well I presume that's right.. Hopefully! It looks complicated enough without all that negative integer stuff! Hopefully I'm right and it's just N!

shawnanana

EvM wrote: »

.

Ah, I have New Concise Project Maths 4 and Im quite sure its not in it . That'd be much appreciated in any case

De moivre's is in New Concise Project Maths 5 on page 60

weirdspider

CookieMonster.x wrote: »

It says in the syllabus 'prove de moivre's theorem by induction for n E N so unless it's written somewhere else I presume we don't?

I'm not sure, my teacher told us we do and she really seems to know her stuff! Sorry to cause any confusion but it may be worth learning if you have extra time to be safe.

yournerd

ahhhhhhhhhhhhhhhhhhhhhhh

lostatsea

weirdspider wrote: »

I'm not sure, my teacher told us we do and she really seems to know her stuff! Sorry to cause any confusion but it may be worth learning if you have extra time to be safe.

She obviously doesn't know her stuff. The syllabus is very clear: Prove De Moivre's for n an element of N. End of story.

weirdspider

aoifemcg94 wrote: »

Please tell me this mainly on about higher maths?
because if not, WHAT :O :L

Yes of course its on Ordinary! What, did you not learn it?!



Jokes

weirdspider

lostatsea wrote: »

She obviously doesn't know her stuff. The syllabus is very clear: Prove De Moivre's for n an element of N. End of story.

Slightly strange how you're making a comment about a person you don't even know... Learn it if you like, its in all the textbooks under the proof for N and I doubt they put it in for no reason.

Monsieur Folie

weirdspider wrote: »

Slightly strange how you're making a comment about a person you don't even know... Learn it if you like, its in all the textbooks under the proof for N and I doubt they put it in for no reason.

My teacher told us we don't need it either; she said the syllabus only specifies it for natural numbers. I wouldn't say it's because your teacher "doesn't know her stuff" though, everyone makes mistakes, especially on such a new course with no clear and concise syllabus and v. few sample papers to draw on.

suitcasepink

Okay lads. if you have 40 mins to learn anything about maths, and you have absolute no strengths in this paper, what do you do??
Do I try learn financial maths? Do I learn some integration and differentiation? Do I go over some learnt off things? What DO I do?

Monsieur Folie

None of this came up in the end, wasting our time learning off stuff when we could have been practicing questions. :P

Undeadfred

You think that someone will do out the paper and put the solutions up online? I'd like to see all the right answers

Vivara

Undeadfred wrote: »

You think that someone will do out the paper and put the solutions up online? I'd like to see all the right answers

Seriously: don't waste your time. Wait for the marking scheme in August, and if then you want, you can view your script.

I can't imagine the kind of stupidity it would take to have a student spend their night doing it out and uploading given that we're faced with a second paper and more on Monday. If it's a teacher, it's another story, but then you'd have to question what kind of teacher is encouraging students to focus on a paper they can no longer do anything about.

Anyway... I thought it was a very manageable paper. A lot of people seemed to think it was very easy. Is this the impression up and down the country or are we all good at maths in my school?

Undeadfred

nah everyone in my school thought it was easy as well

Monsieur Folie

Yeah same really. The people that were worried they were on the verge of failing it came out pretty confident that they're not going to fail now, so that's good. It'll give them a bit of a boost going into P2 so that even if it is a bit harder they'll hopefully manage