## clementchiew 2 years ago how do i show, a is an integer 1) a|0? 2)0|a?

1. zzr0ck3r

does 0 divide anything?

2. clementchiew

no.

3. zzr0ck3r

but I don't see how either show a is an integer, maybe i'm missing something.

4. clementchiew

a is an integer is a condition. i just need to prove it or sth. my textbook is very subtle about requiring wat form of proof.

5. zzr0ck3r

a is an integer if it can be generated by <1>

6. zzr0ck3r

you are saying a is an integer and you need to prove a|0 and 0|a?

7. clementchiew

yeah. or show, as the textbook puts it.

8. zzr0ck3r

well part 1 makes no sense because 0 is in integer and 0 does not divide 0, and the second part makes no sense because nothing divides 0. So you can't prove either.

9. clementchiew

ah well. thanks anyway.

10. zzr0ck3r

is this exactly as the book shows the question?

11. clementchiew

yeah.

12. zzr0ck3r

you can say, if a is an integer and a is not 0, then 0=K*a when k=0, so a|0 because k is an integer (by definition of a|b), for part two nothing divides 0 is your counterexample:)

13. clementchiew

wow. right. thanks.