Américo Tavares

20,672 reputation

334105

bio	website	problemasteoremas.wordpress.c…
	location	Queluz, Portugal
	age	62
visits	member for	2 years, 9 months
	seen	30 mins ago
stats	profile views	5,087

I'm a retired Portuguese electrical engineer.

You can contact me at acltavares[at]sapo[dot]pt

Blog Problemas Teoremas.

MathOverflow account

	20,672 reputation	bio	website	problemasteoremas.wordpress.c…	visits	member for	2 years, 9 months
334105 badges		location	Queluz, Portugal		seen	30 mins ago

summary answers questions tags badges favorites bounties reputation activity

1,934 Favorites

added views newest activity votes

138

273

votes

answers

kviews

Why can you turn clothing right-side-out?

general-topology algebraic-topology

may 20 at 2:36 Double AA 163

122

228

votes

answers

kviews

Mathematical difference between white and black notes in a piano

music-theory

dec 20 at 4:47 Community♦ 1

139

191

votes

answers

kviews

How to study math to really understand it and have a healthy lifestyle with free time?

soft-question advice

dec 31 at 5:24 Grigor 1

108

179

votes

answers

kviews

Is $dy/dx$ not a ratio?

calculus

mar 14 at 3:35 isomorphismes 845

102

176

votes

answers

kviews

Examples of apparent patterns that eventually fail

big-list examples-counterexamples

apr 10 at 3:04 Douglas B. Staple 1,014

131

votes

answers

kviews

Different methods to compute $\sum\limits_{n=1}^\infty \frac{1}{n^2}$

sequences-and-series complex-analysis fourier-analysis big-list faq

mar 8 at 13:57 xpaul 1

120

votes

answers

kviews

Can you answer my son's fourth-grade homework question: Which numbers are prime, have digits adding to ten and have a three in the tens place?

elementary-number-theory recreational-mathematics analytic-number-theory

may 8 at 4:56 Dale M 404

115

votes

answers

kviews

A challenge by R. P. Feynman: give counter-intuitive theorems that can be translated into everyday language

soft-question big-list examples-counterexamples

aug 6 at 1:40 John 1

votes

answers

kviews

In the history of mathematics, has there ever been a mistake?

math-history fake-proofs

apr 28 at 18:46 Pete L. Clark 44.6k

votes

answers

kviews

List of Interesting Math Videos/ Documentaries

soft-question big-list

may 10 at 4:14 cyclochaotic 406

votes

answers

kviews

How many sides does a circle have?

geometry education circle

dec 5 at 20:02 rightfold 103

votes

answers

kviews

Can someone explain the math behind tessellation?

geometry tessellations

may 19 '12 at 8:33 Community♦ 1

votes

answers

kviews

What does $2^x$ really mean when $x$ is not an integer?

algebra-precalculus elementary-number-theory exponentiation

apr 23 '12 at 19:00 Michael Hardy 48.2k

votes

answers

kviews

What remains in student's mind

soft-question education

jun 28 at 22:19 Michael Hardy 48.2k

votes

answers

kviews

Why is Euler's Gamma function the “best” extension of the factorial function to the reals?

real-analysis education gamma-function special-functions

sep 25 at 21:06 Gottfried Helms 7,197

votes

answers

kviews

Tablet for reading textbooks and writing math by hand?

soft-question math-software learning hardware

mar 28 at 16:04 hhh 1,502

votes

answers

kviews

Find a real function, $f$, s.t. $f(f(x)) = -x$.

calculus real-analysis algebra-precalculus functions elementary-functions

feb 25 at 19:56 Jacob Mayle 656

votes

answers

kviews

Prove elementarily that $\sqrt[n+1] {(n+1)!} - \sqrt[n] {n!}$ is strictly decreasing

sequences-and-series

apr 3 at 3:36 Mark Hurd 372

votes

answers

kviews

Best Sets of Lecture Notes and Articles

big-list self-learning learning

may 9 at 21:19 Andrew 1,643

votes

answers

kviews

Is there a definitive guide to speaking mathematics?

reference-request learning pronunciation

apr 6 at 2:19 amWhy 54.7k

votes

answers

kviews

Why can ALL quadratic equations be solved by the quadratic formula?

algebra-precalculus polynomials quadratics

jan 25 at 11:18 George Frank 131

votes

answers

kviews

A Case Against the “Math Gene”

reference-request soft-question education

jun 7 '12 at 17:31 ex0du5 347

votes

answers

732

views

Two curious “identities” on $x^x$,$e$,and $\pi$

integral

nov 26 at 15:22 y zhao 833

votes

answers

kviews

Mathematical equivalent of Feynman's Lectures on Physics?

reference-request education

may 16 at 14:37 Nandhu 1

votes

answers

kviews

Defining a manifold without reference to the reals

general-topology reference-request manifolds

jan 31 '12 at 2:24 Srivatsan 15.6k

votes

answer

kviews

Why are rings called rings?

abstract-algebra terminology math-history

sep 3 '11 at 8:35 t.b. 43.2k

votes

answers

kviews

If $AB = I$ then $BA = I$

linear-algebra matrices

may 1 at 22:19 mezhang 1,403

votes

answers

kviews

Is there an elementary proof that $\sum \limits_{k=1}^n \frac1k$ is never an integer?

number-theory sequences-and-series

nov 27 at 16:40 B.Sahu 1

votes

answers

kviews

Why do books titled “Abstract Algebra” mostly deal with groups/rings/fields?

abstract-algebra soft-question reference-request

jul 7 at 19:25 Uday Reddy 297

votes

answers

kviews

Teenager solves Newton dynamics problem - where is the paper?

differential-equations physics classical-mechanics

jun 8 '12 at 15:58 Américo Tavares 20.7k