den99 wrote:Hello, why in all precalculus books are only odd numbers to answers ? where is even numbers ? How should i know if the answer is correct ? Thx.
I think it's just become the custom. There's no "rule". But if all the answers were provided, how would instructors be able to tell if you'd found any of the answers yourself?
If you're wanting more practice but want the answers, try doing all
the odds, rather than just the ones assigned.