Error in proof that $1 = -1$
43834
Simple Complex Number Problem: $1 = -1$
124584
How to proof that $\forall n \ge 1: \sum_{i=1}^n (i(i+1))^{-1} = n(n+1)^{-1}$ using mathematical induction
77026
Proof with inequalities
2959
Prove $0! = 1$ from first principles
83778
An incorrect proof by exhaustion
78736
Check my proof that $(ab)^{-1} = b^{-1} a^{-1}$
39514
how do I prove that $1 > 0$ in an ordered field?
158862
Show that $a(-1) = (-1)a = -a $.
135807
I'm having trouble with a proof by induction
100399
A doubt with a part of a certain proof.
13899
Proof that $-v = (-1)*v$
31783
Is this proof of $ab = 0$ correct?
56169
What mistakes, if any, were made in Numberphile's proof that $1+2+3+\cdots=-1/12$?
51877
Why is this 'Proof' by induction not valid?
151930
What does it mean by $t=-1$?
80710
Does $\int_{-1}^1 \frac 1 x dx$ equal zero?
135747
Prove $x^{rs}-1=(x^s-1)(x^{s(r-1)}+...+x^s+1)$