Prove if true or find a counterexample....
The product of $x y $ of two real numbers $x$ and $y$ is irrational then at least one of the $x$ or $y$ must be irrational.
Asked
Active
Viewed 1,718 times
-3
-
2http://math.stackexchange.com/questions/507865/check-if-this-proof-about-real-numbers-with-an-irrational-product-is-correct – John Jun 11 '15 at 00:55
-
For many questions you will find that restating the proposition by contraposition will clear up the issue. See the Answer by @mich95 for its application to your Question. – hardmath Jun 11 '15 at 00:59
1 Answers
2
Assume that $x$ and $y$ are rationals, then so is $xy$. That's the contrapositive of your proposition!
mich95
- 8,713
-
4We were within $6$ seconds of each other! I'll delete my answer. $+1$ – Cameron Williams Jun 11 '15 at 00:55