User Javier Badia - Mathematics Stack Exchange

bio	website
	location	Buenos Aires, Argentina
	age	20
visits	member for	2 years, 6 months
	seen	1 hour ago
stats	profile views	229

	2,542 reputation	bio	website		visits	member for	2 years, 6 months
1522 badges		location	Buenos Aires, Argentina		seen	1 hour ago

3

votes

1

answer

81

views

Tips on this olympiad problem

contest-math

may 11 at 2:31 Ivan Loh 6,508

2

votes

0

answers

37

views

Intuitive understanding of integral of vector valued functions

apr 24 at 18:27 Amzoti 13.9k

4

13

votes

1

answer

125

views

Is there any meaning to an “infinite derivative”?

calculus derivatives

apr 16 at 0:00 Micah 6,405

1

8

votes

3

answers

142

views

Does $a^n \mid b^n$ imply $a\mid b$?

elementary-number-theory divisibility

apr 5 at 9:53 TMM 7,156

2

4

votes

2

answers

117

views

Calculating $\int_0^\infty(\log t)^n e^{-t}\ dt$

calculus integral improper-integrals

mar 17 at 1:43 Mhenni Benghorbal 13.8k

2

votes

1

answer

80

views

How can the graph of a complex function be embedded in three dimensional space?

complex-analysis

jan 3 at 0:29 espen180 1,396

3

votes

2

answers

79

views

Why do we get two solutions when inverting $y = \sinh x$?

algebra-precalculus hyperbolic-functions

dec 26 at 23:09 Marc van Leeuwen 23.6k

1

vote

0

answers

80

views

Is my formula for the change of basis of an inner product correct?

linear-algebra inner-product-space

nov 28 at 22:36 Javier Badia 2,542

6

votes

3

answers

342

views

Difference between $\implies$ and $\;\therefore\;\;$?

logic notation proof-writing

nov 17 at 17:22 amWhy 53.9k

1

10

votes

5

answers

493

views

Solving $\lim\limits_{x \to 0^+} \frac{\ln[\cos(x)]}{x}$

calculus limit

nov 4 at 20:10 Chris's wise sister 11.5k

1

3

votes

1

answer

88

views

Proving statement about dimensions of vector spaces

linear-algebra

sep 30 at 14:41 Ayman Hourieh 11.1k

0

votes

1

answer

32

views

Help with a linear algebra problem; defining a function with some properties

linear-algebra

sep 29 at 15:05 Berci 20.5k

3

votes

1

answer

144

views

What is it called when a function is not continuous but still can have a derivative?

calculus derivatives

sep 24 at 16:25 Siminore 7,860

0

votes

0

answers

64

views

How do you explain the appearance of a sine in the integral for calculating the surface area of a sphere?

geometry surfaces

sep 23 at 2:48 Javier Badia 2,542

1

2

votes

2

answers

290

views

Basic group theory exercise

group-theory

aug 10 at 2:10 Brian 1,364

6

votes

5

answers

655

views

Proving that $\lim\limits_{x \to 0}\frac{e^x-1}{x} = 1$

limit derivatives

aug 2 at 0:12 jon jones 379

1

vote

1

answer

79

views

Having trouble understanding proof of a theorem involving limits of functions and sequences

calculus sequences-and-series limit

jul 25 at 19:13 user29999 1,745

7

votes

2

answers

286

views

Motivation for definition of logarithm in Feynman's Lectures on Physics

logarithms

jul 18 at 19:28 Michael A. Gottlieb 61

5

votes

2

answers

161

views

How do we know that $\exp(x)$ agrees with raising a number to a rational power?

exponentiation

jul 7 at 2:04 J. M. 38.9k

1

2

votes

1

answer

174

views

Does this weird sequence have a limit?

sequences-and-series limit

jun 30 at 14:51 Ilmari Karonen 8,226

2

11

votes

4

answers

1

kviews

If a function has a finite limit at infinity, does that imply its derivative goes to zero?

calculus limit derivatives

jun 24 at 4:46 Dason 99

1

vote

1

answer

114

views

Confused about Wikipedia page on differential forms

differential-forms

may 17 '12 at 23:11 Jeff 1,082

2

votes

1

answer

372

views

How to prove $\lim_{(x,y)\to(0,0)} \frac{xy}{x+y} = 0$

limit multivariable-calculus

may 4 '12 at 21:16 Arturo Magidin 158k

1

vote

2

answers

224

views

Can I apply Rolle's theorem in reverse?

homework real-analysis

apr 30 '12 at 17:18 Javier Badia 2,542

0

votes

2

answers

49

views

Proving statement about sequences

homework sequences-and-series

apr 27 '12 at 18:34 Tomarinator 1,138

2

0

votes

3

answers

760

views

Proving limit doesn't exist using the $\epsilon$-$\delta$ definition

limit

apr 14 '12 at 22:41 Gustavo Marra 1,642

0

votes

2

answers

69

views

Would like some pointers on this geometry problem

geometry

apr 5 '12 at 16:00 Wonder 2,524

0

votes

0

answers

159

views

Prove that $\mathbb{R}_{>0}$ is not bounded from above

homework proof-writing

mar 21 '12 at 21:55 Javier Badia 2,542

3

votes

2

answers

157

views

Are there exact expressions for $\sin \frac{3\pi}{8}$ and $\cos \frac{3\pi}{8}$?

trigonometry complex-numbers

mar 13 '12 at 3:09 André Nicolas 160k

1

vote

1

answer

107

views

How to solve $y'' = -\frac{k}{y^2}$, with $k > 0$?

differential-equations

feb 29 '12 at 0:44 Javier Badia 2,542

Javier Badia

41 Questions