User bobobobo - Mathematics Stack Exchange

bio	website	bobobobo.wordpress.com
	location	Canada
	age
visits	member for	2 years, 9 months
	seen	May 8 at 18:03
stats	profile views	495

	2,042 reputation	bio	website	bobobobo.wordpress.com	visits	member for	2 years, 9 months
929 badges		location	Canada		seen	May 8 at 18:03

28

33

votes

5

answers

3

kviews

Getting better at proofs

soft-question proof-strategy

oct 28 '10 at 23:25 Qiaochu Yuan 118k

9

27

votes

5

answers

1

kviews

Dominoes and induction, or how does induction work?

intuition induction

aug 1 at 6:11 Dan Christensen 1,575

5

20

votes

6

answers

1

kviews

Why do we need to prove $e^{u+v} = e^ue^v$?

exponentiation teaching

oct 13 '11 at 1:45 J. M. 38.9k

1

12

votes

2

answers

295

views

Why isn't $ SA_{\text{cube}} = 3x^2 $?

geometry

jun 16 '11 at 23:29 amWhy 55.1k

4

10

votes

2

answers

262

views

What are all these “visualizations” of the 3-sphere?

geometry general-topology visualization hopf-fibration

may 26 '12 at 8:36 Patch 631

13

9

votes

3

answers

1

kviews

If $\frac{dy}{dt}dt$ doesn't cancel, then what do you call it?

calculus notation

mar 18 '11 at 19:47 ja72 1,714

8

votes

1

answer

193

views

Can you approximate a vector field?

multivariable-calculus

may 10 at 6:03 Community♦ 1

2

8

votes

5

answers

574

views

Is $\lim\limits_{n \to \infty}\frac{1}{n}\left( \cos{\frac{\pi}{n}} + \cos{\frac{2\pi}{n}} + \ldots + \cos{\frac{n\pi}{n}} \right)$ a Riemann sum?

calculus integral limit

apr 6 at 20:54 user17762 76.4k

4

8

votes

1

answer

458

views

$\arcsin$ written as $\sin^{-1}(x)$

trigonometry notation faq

jul 20 at 0:20 J. M. 38.9k

1

8

votes

1

answer

2

kviews

What is a “vanishing moment”?

wavelets

apr 4 '12 at 23:38 EMS 1,139

2

8

votes

4

answers

474

views

Why is the 2nd derivative written as $\frac{\mathrm d^2y}{\mathrm dx^2}$?

calculus notation

aug 21 '11 at 17:04 Ben Crowell 2,440

1

7

votes

4

answers

269

views

The leap to infinite dimensions

linear-algebra functions fourier-series infinity

jul 20 '11 at 5:56 Samuel 2,537

2

6

votes

1

answer

427

views

Why is it called a 'ring', why is it called a 'field'?

abstract-algebra terminology ring-theory field-theory

oct 9 '11 at 23:16 mixedmath♦ 27.3k

6

votes

2

answers

185

views

Improper integrals question: why does this work?

intuition limit improper-integrals

apr 29 '11 at 15:41 Jonas Meyer 35.1k

1

6

votes

1

answer

484

views

Prove the reduction formula

calculus integral

apr 3 '11 at 1:35 Arturo Magidin 158k

3

5

votes

3

answers

380

views

Why do we use n-dimensional spaces?

vector-spaces

mar 13 at 12:40 Byron Schmuland 15.4k

2

5

votes

3

answers

227

views

How to think of a function as a vector?

functions vector-spaces

may 28 '12 at 17:21 anon 40k

1

5

votes

1

answer

489

views

Finding integrating factor when IF will be a function of x and y

differential-equations pde

may 1 '12 at 4:58 tentaclenorm 388

5

votes

1

answer

268

views

How do we know the complex exponentials “span” the set of all real functions?

fourier-analysis

apr 7 '12 at 0:51 Matt E 58.1k

2

5

votes

4

answers

2

kviews

Solving very large matrices in “pieces”

linear-algebra algorithms matrices

may 12 '11 at 12:05 J. M. 38.9k

2

5

votes

2

answers

352

views

Intuition behind arc length formula

calculus functions intuition

mar 20 '11 at 4:30 Arturo Magidin 158k

1

4

votes

4

answers

572

views

Why is the differential solid angle have a $\sin\theta$ term in integration in spherical coordinates?

integration spherical-coordinates solid-angle

jan 10 at 3:56 hhh 1,500

1

4

votes

1

answer

386

views

Integral $ \int_0^{2\pi}{ \sqrt{ 1 - \sin{ \theta } \sin{ 2\theta } + \cos{\theta}\cos{2\theta} } d\theta } $

integral trigonometry

jan 28 '12 at 17:34 Clive Newstead 15.3k

4

votes

3

answers

158

views

Integrating $ \frac{1}{\mathrm{e}^{2\, t}\, \left(\mathrm{e}^{t} + 1\right)} $

integral

may 31 '11 at 20:54 Lyrebird 498

4

votes

2

answers

272

views

Trig integral $\int{ \cos{x} + \sin{x}\cos{x} dx }$

calculus integral trigonometry

apr 15 '11 at 19:20 Jack 7,521

4

votes

2

answers

2

kviews

Is there a name for sec(x)'s relationship with tan(x)?

trigonometry

apr 6 '11 at 4:58 Robert Israel 86.4k

4

votes

1

answer

186

views

Formula for $\sum_{k=1}^n \frac{10}{10+k}$

sequences-and-series

jan 15 '11 at 22:01 Rasmus 9,458

4

votes

2

answers

297

views

Prove $D_x(\int_a^x f(t)dt) = f(x)$

calculus

nov 8 '10 at 13:05 Paxinum 1,601

1

3

votes

5

answers

2

kviews

Integral $\int{\sqrt{25 - x^2}dx}$

calculus integral

mar 20 at 17:43 Ellipsoid 44

1

3

votes

3

answers

778

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Bilinearity: what does it mean?

linear-algebra terminology intuition bilinear-form

mar 7 at 11:43 azimut 5,503

bobobobo

79 Questions