# Thread: Help with rationality proof

1. ## Help with rationality proof

Hello all, i could use some help with a problem i cant quite figure out how to prove. I'll keep trying, but any help in the meantime would be greatly appreciated.

"If x^4 is irrational, then x is irrational" ...Prove true for all Real #'s.

Is the converse true for all Real #'s x ? (If x is irrational, then x^4 is irrational)

Thank you,

Kyle

2. Originally Posted by CSkyle
Hello all, i could use some help with a problem i cant quite figure out how to prove. I'll keep trying, but any help in the meantime would be greatly appreciated.

"If x^4 is irrational, then x is irrational" ...Prove true for all Real #'s.

Is the converse true for all Real #'s x ? (If x is irrational, then x^4 is irrational)

Thank you,

Kyle

Try proof by contraposition

not Q implies not P

if x is rational then x^4 is rational.

This should be easier.

the second is not try $\displaystyle \sqrt2$

3. nice, thats way easier. thanks empty.