What is wrong with my proof: $-1 = 1$?
6650
Why $\sqrt{-1 \times -1} \neq \sqrt{-1}^2$?
35556
$f(z)=\frac{z}{1+|z|} $ Is 1-1?
116043
Why is a raised to the power of Zero is 1?
154133
Flawed proof by induction that $a^{n-1}=1$
147986
Prove: if $|z|=1$ than $\frac{z+1}{z-1}$ is an imaginary number
141540
What is wrong with the following "proof" that $e=1$?
19628
What is wrong with this fake proof $e^i = 1$?
13899
Proof that $-v = (-1)*v$
110643
What are the strategies I can use to prove $f^{-1}(S \cap T) = f^{-1}(S) \cap f^{-1}(T)$?
95057
Possible fake proof of $1= -1$
155897
Proof by induction - is this correct?
5347
Using the definition of a vector space to prove that $0x = 0$ and $(-1)x = -x$
80648
What's $(-1)^{2/3}\; $?
41204
Why do I get one extra wrong solution when solving $2-x=-\sqrt{x}$?
154945
$|px^2+qx+r|\le1$ for all $x$ in $[-1; 1]$, show that $|rx^2+qx+p|\le2$ for all $x$ in $[-1; 1]$
36436
Proving $\sum_{k=1}^n k k!=(n+1)!-1$
101169
Prove that $x^2 = - 1$ has no solution in $\mathbb{Z}$