The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

Try Work out this maths question ;)

Disprove this statement by providing a counterexample, n is an integer

"If n^3 is divisible by 8, then n is divisible by 8"
Original post by X1PRINCE
Disprove this statement by providing a counterexample, n is an integer

"If n^3 is divisible by 8, then n is divisible by 8"


n=2n = 2
Original post by RDKGames
n=2n = 2

Ha ha, don't look to me for the answer XD, I'm just a maths A level student trying to figure out what the answer and working out is to it lol. But if you input 2 the statement is right, however the question asks to disprove, I don't think it's simple as giving the number. Can you help me put this in the maths group please :smile:
Reply 3
Avatar for BillyMic
BillyMic
9
I mean 2^3 = 8.
Original post by X1PRINCE
Ha ha, don't look to me for the answer XD, I'm just a maths A level student trying to figure out what the answer and working out is to it lol. But if you input 2 the statement is right, however the question asks to disprove, I don't think it's simple as giving the number. Can you help me put this in the maths group please :smile:

The question states ‘by counterexample’. N = 2 is a counterexample :smile:
Original post by X1PRINCE
Ha ha, don't look to me for the answer XD, I'm just a maths A level student trying to figure out what the answer and working out is to it lol. But if you input 2 the statement is right, however the question asks to disprove, I don't think it's simple as giving the number. Can you help me put this in the maths group please :smile:


Er... no this is a very simple question and n=2n=2 disproves it.

2^3 = 8 is divisible by 8

but 2 on its own is not divisible by 8.
N = 4 as well lol. :smile:
Reply 7
Avatar for BillyMic
BillyMic
9
Original post by PepeIsAngry
N = 4 as well lol. :smile:


Why 4 as 4^3 is 64?
64 is divisible by 8 but 4 isn't.
Reply 9
Avatar for BillyMic
BillyMic
9
Original post by PepeIsAngry
64 is divisible by 8 but 4 isn't.


Smart stuff, thanks for telling me.
Huh, that's wierd it's a 2 mark question lol XD.
Original post by X1PRINCE
Huh, that's wierd it's a 2 mark question lol XD.


One mark for a valid n value, and another for your reasoning. Probably. It's a typical weight for such a question.
Original post by RDKGames
One mark for a valid n value, and another for your reasoning. Probably. It's a typical weight for such a question.

Probably is, lol thanks. Looked at the A Level Paper thought it was going to be a big questions. Turns out it's a simple question :wink:

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you