Explanation of why $-1 = \sqrt{-1} \times\sqrt{-1} = \sqrt{(-1)^2} = \sqrt{1} = 1$ is true/false?
3712
Why $\sqrt{-1 \cdot {-1}} \neq \sqrt{-1}^2$?
83753
Why $\,p \cdot (p^{-1} \mod q) + q \cdot (q^{-1} \mod p) = pq + 1$?
6721
math fallacy problem: $-1= (-1)^3 = (-1)^{6/2} = \sqrt{(-1)^6}= 1$?
155995
Fibonacci proof question: $f_{n+1}f_{n-1}-f_n^2=(-1)^n$
80004
Why is $1/i$ equal to $-i$?
110826
prove that : $ i = \sqrt {-1}\ $
17515
Why is negative times negative = positive?
110661
When does $\sqrt{a b} = \sqrt{a} \sqrt{b}$?
14633
What's the thing with $\sqrt{-1} = i$
151930
What does it mean by $t=-1$?
59872
How to prove $\inf(S)=-\sup(-S)$?
81238
Is $O(2)$ really not isomorphic to $SO(2)\times \{-1,1\}$?
78736
Check my proof that $(ab)^{-1} = b^{-1} a^{-1}$
5526
Prove that $ℤ[i]^*= \{1,-1,i,-i\}$
22129
Why is $\sqrt{\sum_{i=1}^n |v_i|^2} \leq \sum_{i=1}^n |v_i|$ true?
109674
If $(I-T)^{-1}$ exists, can it always be written in a series representation?
149553
Is it always true that $(A_1 \cup A_2) \times (B_1 \cup B_2)=(A_1\times B_1) \cup (A_2 \times B_2)$