can not find the mistake in this proof.
3712
Why $\sqrt{-1 \cdot {-1}} \neq \sqrt{-1}^2$?
6443
Is there a proof for this Fibonacci relationship?
50266
In the following figure prove that: $AK||BC$
115506
What's wrong with this demonstration? (1 = -1)
139841
Proving $A\setminus(B\setminus C)$ is not equal to $(A\setminus B)\setminus C$
149064
Referee says the proof is wrong, but it is not, what to do?
39908
Finding the error in this proof that 1=2
50804
It seems obvious, but how to prove it formally?
20658
Difficulty in finding a counterexample
73683
Proof by induction - Being stuck before being able to prove anything!
61604
$V = V_1 + V_2$ confusion? Why is my "proof "incorrect?
93606
Showing that $C[0,1]$ is not complete
135807
I'm having trouble with a proof by induction
88188
Explain proof by contradiction.
34758
Cancellation Law for Direct Sums - What is wrong with this argument?
141540
What is wrong with the following "proof" that $e=1$?
100399
A doubt with a part of a certain proof.