Thanks for taking the time to verify my approach and as well as my answer.
Background:
- B.S. in Business from a 4-year university taking CS courses online
- I would like some help with a basic proof from MIT's 6.042J Mathematics for Computer Science course.
The question is:
Prove $\log_{4}6$ is irrational.
We prove the contradiction.
- Suppose $\log_{4}6$ is rational (i.e. a quotient of integers)
$$\log_{4}6 = m/n$$ - So we must have m, n integers without common prime factors such that
$$4^{m/n} = 6$$ - We will show that m and n are both even
$$(4^{m/n})^{n} = 6^{n}$$ - So
$$4^{m} = 6^{n}$$ - We then divide the two base numbers by their common factor, $2$, which gives us:
$$2^{m} = 3^{n}$$
- Since the product of two even numbers must be even AND the product of two odd numbers must be odd, $2^{m}$ and $3^{n}$ are not equivalent and therefore $m/n$ must not be rational.
Q.E.D. We conclude that $\log_{4}6$ is irrational.
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