Prove that expression is never an perfect square.
60615
Product of $5$ consecutive integers cannot be perfect square
93606
Showing that $C[0,1]$ is not complete
21906
Show $3^m + 3^n +1$ cannot be a perfect square for $m,n$ being positive integers.
94682
Polynomial: prove there is no double root
22973
Show that an integer of the form $8k + 7$ cannot be written as the sum of three squares.
65895
Irrationality proofs not by contradiction
67031
use contradiction to prove that the square root of $p$ is irrational
155170
Proving $\sin(x^2)$ Continuous but Not Uniformly Continuous with non-standard Definition
78804
Proving that $\mathscr L=\{0^n \big|\text{n is the square of a natural number }\}$ is non regular using the pumping lemma
33628
Prove that $\sin(\sqrt x)$ not periodic
127566
$2AB$ is a perfect square and $A+B$ is not a perfect square
19588
$n!+1$ being a perfect square
75639
Showing that $\sqrt[3]{2}\notin\Bbb Q(\alpha_1,...,\alpha_k)$ where $\alpha_i^2\in\Bbb Q\ \forall i$
149071
Let $d$ be any positive integer not equal to $2, 5,$ or $ 13$ , then $\exists a, b \in \{2, 5, 13, d\}$ such that $ab − 1$ is not a perfect square?
34666
Prove that the expression cannot be a power of 2
77464
Prove that ${x dy - y d x\over x^2 + y^2}$ is not exact
113344
How do we prove that something is unprovable?