Is there any flaw in the proof of $-1 = 1$?
3712
Why $\sqrt{-1 \cdot {-1}} \neq \sqrt{-1}^2$?
100399
A doubt with a part of a certain proof.
56169
What mistakes, if any, were made in Numberphile's proof that $1+2+3+\cdots=-1/12$?
59006
Proof of $\gcd(n!+1, (n+1)!+1)=1$?
80710
Does $\int_{-1}^1 \frac 1 x dx$ equal zero?
80144
Prove that $x-1$ divides $x^n-1$
101169
Prove that $x^2 = - 1$ has no solution in $\mathbb{Z}$
13899
Proof that $-v = (-1)*v$
65923
How to approach proving $f^{-1}(B\setminus C)=A\setminus f^{-1}(C)$?
19628
What is wrong with this fake proof $e^i = 1$?
89535
fake proof of $\forall a. \forall b. a = b \to 1 = 0$
111938
How do I find a flaw in this false proof that $7n = 0$ for all natural numbers?
87848
Formal proof for $(-1) \times (-1) = 1$
111505
Proof $\binom{p-1}{k}\equiv (-1)^k \mod{p}$
80004
Why is $1/i$ equal to $-i$?
68092
Does square difference prove that 1 = 2?
107390
Why is (-1)(-1) = 1?