Given d,d′ are in Z>1, and gcd, and d \mid n and d'\mid n,
Show that d\cdot d'\mid n.
I pretty much have it but I think it could be made more clear. I have:
d \mid n so n=q*d and d'\mid n so n=q'*d'
So q*d*q'*d'=n^2
So (q*d*q'*d')/n=n
So (q*q'/n)*(d*d')=n ... so the only thing left to do is show that q*q'/n must be an integer.
I think it has something to do with \gcd(d,d')=1 because d and d' cannot both divide an integer n unless n is a multiple of d*d', but I'm not sure how to show this elegantly.
Thanks!
Answer
Hint: since \gcd(d, d') = 1, there exist \alpha, \beta \in \mathbb{Z} such that \alpha d + \beta d' =1. Now multiply both sides by n, and use the fact that d \mid n and d' \mid n. Feel free to comment if you need further clarification!
No comments:
Post a Comment