# Cambridge Chat (previously New Cambridge Students Entry 2004)

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French Pikachu
It was mine too! I'm officially not a baby anymore and totally legal for drinking, clubbin....! But i can also go to jail now hehe the joy of being 18!

EDIT: hehe i just realised it is still my birthday in UK coz it's - 1H with France...

being old sucks, and remember that.
Hey guys - remember me from the mists of time past worrying last summer?

Hope you are all ok and not stressing about exams
Fluffstar
Hey guys - remember me from the mists of time past worrying last summer?

Hope you are all ok and not stressing about exams

Course we remember you!

And nah, I've lost all hope now

A.
i want to goto the library but I'm scared my bedder will come in here and killlll me for having the messiest room ever
homoterror
i want to goto the library but I'm scared my bedder will come in here and killlll me for having the messiest room ever

No, I think mine wins at the moment. I'm being such a hobo at the moment. It really is quite inhospitable, the bedder is definitely not allowed in until it's been decontaminated.

A.
Guess what Guess what!!!! I can do some of the discrete maths!!!!!!! I managed to answer a question without having to look at my notes!!! If only I had another month of revision time then I might actually be able to do exam questions on this damn topic!
OOO OOO OOO:

Can someone check my proof for the following:

Prove that the set of irrational numbers is uncountable...

For this I said take the set I as the set of irrationals. R = Q U I
i.e. that the real numbers is the union of the rationals and irrationals
But we know R is irrational and Q is rational, and so using the property that the union of countable sets is countable, I must be uncountable!

Is that right? Is there any other way to do it (which isnt horrendously complex mind you!)
Bah bah bah... turn me into a sheep dude... Just DO IT!!
Willa
OOO OOO OOO:

Can someone check my proof for the following:

Prove that the set of irrational numbers is uncountable...

For this I said take the set I as the set of irrationals. R = Q U I
i.e. that the real numbers is the union of the rationals and irrationals
But we know R is irrational and Q is rational, and so using the property that the union of countable sets is countable, I must be uncountable!

Is that right? Is there any other way to do it (which isnt horrendously complex mind you!)

irrational numbers... ah yes... proof by contradiction is the easiest way to do it. Alternatively, you can try diagonal argument.
so how would you do it as a proof by contradiction? Or the diagonal argument as well...I cant see how to use that (probably cos I dont understand it properly)!!??
Willa
so how would you do it as a proof by contradiction? Or the diagonal argument as well...I cant see how to use that (probably cos I dont understand it properly)!!??

You basically just used proof by contradiction.

I wouldn't bother with diagonal argument. It makes me woozy.
Oh, but it is fun!
Willa
so how would you do it as a proof by contradiction?

That's exactly what you just did, say so in your answer. Makesure you've also proved there isn't a bijection from N to R if you haven't used done that already in the question. I remember there being questions which made you go all the way back through to N rather than assuming the uncountablity of R.

A.
Alaric
That's exactly what you just did, say so in your answer. Makesure you've also proved there isn't a bijection from N to R if you haven't used done that already in the question. I remember there being questions which made you go all the way back through to N rather than assuming the uncountablity of R.

A.

I suppose it depends on how many marks the question carry... you wouldn't prove R is uncountable for 2 marks would you? (having said that... you might have to if a quest explicitly asked for it...)
Oh Goat... Fill me with coffee your Lordies.

ps, mix coffee with coke taste funny.
Camford
I suppose it depends on how many marks the question carry... you wouldn't prove R is uncountable for 2 marks would you? (having said that... you might have to if a quest explicitly asked for it...)

2003 P1 Q8 - my paper 1 in my first year. Prove R is uncountable. 2 marks. Bastards.

I don't think I did too badly on that question though. Maybe 6 - 10 marks.

A.
You guys have just destroyed any shred of doubt I had left about my decision not to do a maths degree.
Allyria
You guys have just destroyed any shred of doubt I had left about my decision not to do a maths degree.