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
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	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

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Getting better at proofs

soft-question proof-strategy

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

1

8

votes

1

answer

2

kviews

What is a “vanishing moment”?

wavelets

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

1

3

votes

2

answers

2

kviews

Spherical harmonics for dummies

spherical-harmonics

aug 2 '11 at 14:17 bobobobo 2,042

1

3

votes

5

answers

2

kviews

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

calculus integral

mar 20 at 17:43 Ellipsoid 44

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

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

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

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

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

0

votes

1

answer

1

kviews

Can you not rotate spherical coordinates?

linear-algebra spherical-coordinates

aug 24 '11 at 15:26 Willie Wong♦ 30.7k

1

3

votes

4

answers

1

kviews

Infinitely differentiable

calculus

dec 10 '10 at 15:47 Community♦ 1

1

2

votes

1

answer

812

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How to add cosines with different phases using phasors

complex-numbers

nov 5 '11 at 9:55 Heike 1,016

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 5,498

1

3

votes

4

answers

645

views

Are sin and cos the only continuous and infinitely differentiable periodic functions we have?

trigonometry periodic-functions

nov 20 at 4:11 doraemonpaul 3,026

1

0

votes

1

answer

602

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Cardan angle (zxz, zxzxz) rotation

rotations

oct 7 '11 at 23:03 Henning Makholm 53.6k

2

8

votes

5

answers

574

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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

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

3

votes

1

answer

532

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How to prove spherical harmonics are orthogonal

orthonormal spherical-harmonics

jun 4 '12 at 14:35 Community♦ 1

0

votes

1

answer

497

views

Rotation matrices using a change-of-basis approach

linear-algebra rotations

jul 23 '11 at 19:46 Willie Wong♦ 30.7k

1

5

votes

1

answer

488

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

differential-equations pde

may 1 '12 at 4:58 tentaclenorm 388

1

6

votes

1

answer

484

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Prove the reduction formula

calculus integral

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

2

8

votes

4

answers

474

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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

2

votes

3

answers

465

views

How do I find if two triangles are adjacent, when they differ in size?

geometry

sep 6 '10 at 5:39 David Lewis 1,080

4

8

votes

1

answer

457

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

trigonometry notation faq

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

2

6

votes

1

answer

427

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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

1

vote

2

answers

404

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A cylinder is not always can-shaped?

geometry

mar 23 '11 at 2:25 Jonas Meyer 35.1k

2

votes

5

answers

404

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$\lim\limits_{x \to \infty}\frac{2^x}{3^{x^2}}$

limit

feb 9 '11 at 6:24 Gottfried Helms 7,217

1

4

votes

1

answer

386

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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

3

5

votes

3

answers

380

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Why do we use n-dimensional spaces?

vector-spaces

mar 13 at 12:40 Byron Schmuland 15.4k

1

vote

2

answers

363

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Is convolution in spherical harmonics equivalent to multiplication in the spatial domain?

convolution spherical-harmonics

feb 10 at 14:07 Devsh 1

bobobobo

79 Questions