A problem in algebra: how does $-1=1$?
6721
math fallacy problem: $-1= (-1)^3 = (-1)^{6/2} = \sqrt{(-1)^6}= 1$?
96554
Why is $x^0 = 1$ except when $x = 0$?
5526
Prove that $ℤ[i]^*= \{1,-1,i,-i\}$
13012
Why can a = b imply 2 = 1?
41204
Why do I get one extra wrong solution when solving $2-x=-\sqrt{x}$?
97952
Square root of 1 is (not) -1
45037
Show $(2^m-1,2^n+1)=1$ if $m$ is odd
27802
How to show this equals 1 without "calculations"
14633
What's the thing with $\sqrt{-1} = i$
108244
Proof without solving equation that if $(1+z)^n = (1-z)^n$ then Re(z) = 0. Did I do it right?
81875
why is $\sqrt{-1} = i$ and not $\pm i$?
33184
Something strange about $\sqrt{ 4+ \sqrt{ 4 + \sqrt{ 4-x}}}=x$ and its friends
89705
How to solve $a_n = 2a_{n-1} + 1, a_0 = 0, a_1 = 1$?
158335
Why is this $0 = 1$ proof wrong?
80004
Why is $1/i$ equal to $-i$?
10548
The equation $-1 = x^2 + y^2$ in finite fields
6650
Why $\sqrt{-1 \times -1} \neq \sqrt{-1}^2$?