Using contrapositive to Prove that if an average of a thousand numbers is less than 7, then at least one of the numbers being averaged is less than 7
100613
Prove that if an average of a thousand numbers is less than 7, then at least one of the numbers being averaged is less than 7
33998
Show that given seven real numbers, it is always possible take two of them, such that $\left\vert\frac{a-b}{1+ab}\right\vert<\frac{1}{\sqrt{3}}$
101899
Proof By Induction of a Sum
72185
The negation of a limit condition, Spivak style.
136274
$n! \leq \left( \frac{n+1}{2} \right)^n$ via induction
141529
Proving existence of a minimum
20658
Difficulty in finding a counterexample
95057
Possible fake proof of $1= -1$
100565
Property of sup of a set of numbers
40048
Finding the fallacy in this broken proof
100399
A doubt with a part of a certain proof.
1841
Show that if terms of a series have ratio less than the ratio of convergent series, then the series converges
138632
Proof that if $a > 0$, then $\frac{1}{a} > 0$ using just field and order axioms
106979
Prove the inequality and limitation
66104
Showing that something is a sufficient statistic
1401
$\sqrt{7\sqrt{7\sqrt{7\sqrt{7\sqrt{7\cdots}}}}}$ approximation
111938
How do I find a flaw in this false proof that $7n = 0$ for all natural numbers?