Irrationality of roots

For two integers m , n > 1 m, n > 1 such that m m is not a perfect n th n^{\text{th}} power, m n \displaystyle \sqrt[n]{m} is certainly an irrational number.

True \text{True} False \text{False} Cannot be determined \text{Cannot be determined}

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

2 solutions

Matin Naseri
Jan 22, 2018

details show m,n>1 \text{m,n>1}
The minimize possible for that m n \sqrt[n]{m} such that n t h \text{n}^{th} isn't perfect is 2 2 \sqrt[2]{2} =irrational \text{=irrational} thus the mentioned statement is true \text{true} .

Awesome explanation.

Sarfarz Saifie - 3 years, 4 months ago
Akeel Howell
Jan 22, 2018

Assume that m n = p q \sqrt[n]{m} = \dfrac{p}{q} for positive integers p , q p,q . Then m = ( p q ) n m = \left( \dfrac{p}{q} \right) ^n .

Therefore, m q n = p n mq^n = p^n . By the fundamental theorem of arithmetic, p , q p,q are multiples of a set of primes repeated n n times. But then the prime factors of m m do not repeat n n times (since m m is not a perfect n th n^{\text{th}} power).

So m q n p n mq^n \ne p^n .

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...