Maths AS level Q HELP!

If you let n be a cube number then n=m^3 for some integer n.

If m is a multiple of 3, m=3k for some integer k. So then n=m^3 --> n=27k^3 = 9(3k^3) which is obviously a multiple of 9.

If m isn't a multiple of 3, it must eitther leave remainder 1 or 2 after division so call this case A:

Can you now finish the proof?

that's great thanks!

No problem - this is an interesting problem, may I ask where you got it from?

No problem - this is an interesting problem, may I ask where you got it from?

I found it in the year 1 OCR A maths book for AS level

It seems like the diffferent textbooks are copying each other

It's in the Edexcel Year 1 textbook in the proof by exhaustion exercise. I think a real exam question would give hints on how to split it up into different cases.

I found it in the year 1 OCR A maths book for AS level

Ah yes it probably would. If it just gave you this problem without setting it up from earlier parts, I'd imagine it'd be for the A* students?

I don't think you'd see it in an A Level exam at all so I wouldn't even say it's for A* students. There haven't been enough specimen papers yet so I may be wrong...