Irrationality of $\cos 2\pi / n$
120065
Niven’s theorem proof.
65895
Irrationality proofs not by contradiction
15110
About irrational logarithms
32848
Prove that the product of a non-zero rational and irrational number is irrational.
11069
Deciding whether $2^{\sqrt2}$ is irrational/transcendental
77129
Density of irrationals
53945
The square root of a prime number is irrational
44573
Can $\pi$ be rational in some base radix
50555
Approximation of real number to the power of irrational
13592
How can $\pi$ be irrational if it can be calculated using an infinite series of rational numbers?
128298
Irrationality of sum of two logarithms: $\log_2 5 +\log_3 5$
66872
Exact values of $\cos(2\pi/7)$ and $\sin(2\pi/7)$
30622
Proving $\sqrt 3$ is irrational.
127830
proof that $\sqrt(2)$ is irrational / why is the fraction irreducible
109175
Why is it hard to prove whether $\pi+e$ is an irrational number?
59391
$p,q,r$ primes, $\sqrt{p}+\sqrt{q}+\sqrt{r}$ is irrational.
28347
Prove that $\sqrt 2 + \sqrt 3$ is irrational