- #1
RJLiberator
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Homework Statement
Show that if a, b, n, m are Natural Numbers such that a and b are relatively prime, then a^n and b^n are relatively prime.
Homework Equations
Relatively prime means 1 = am + bn where a and b are relatively prime. gcd(a,b) = 1
We have a couple corollaries that may be beneficial:
1. Suppose a, n are positive integers. Then a and a^n have the same prime factors.
2. Let a, n be positive integers. a^(1/n) is either an integer or it's irrational.
The Attempt at a Solution
By definition of relatively prime, 1 = ax + by where x,y exist as integers.
By the fundamental theorem o arithmetic:
a = p1*p2*...*pm where this is the unique prime factorization.
b = p1*p2*...*pd
m,d are natural numbers.
By the corollarly, a^n = p1^n*p2^n*...*pm^n
b^n = p1^n*p2^n*...*pd^n
So we start with
1 = ax + by
1 = (p1*p2*...*pm)*x + (p1*p2*...*pd)y****All I have left to do is find the way to raise this to the power of n. If I can raise it such that
1^n = (ax)^n + (by)^n the proof is done, easily, with what I have set up.
Question: Is this step needed? Can I just use the corollary to say that "by the corollary" since a and a^n have the same prime factorization and b and b^n have the same prime factorization, then we see a^n and b^n must be relatively prime?