Mathematics
Blue's user avatar
Blue's user avatar
Blue's user avatar
Blue
  • Member for 13 years, 2 months
  • Last seen this week
Profile Activity
Stats
73,802
reputation
3.0m
reached
1,396
answers
6
questions
Communities
View all
About

  • Follow @blue on mathstodon.xyz, the mathy Mastodon instance.

  • See my (Tee)Spring shop, "Inspired by Math", for t-shirts featuring some of my mathy
    designs that have become somewhat popular on Math.SE.

  • My Etsy shop, also "Inspired by Math", has posters. (Want a particular design? Tell me!)

  • Contact me via the "Email the Trigonographer" link at trigonography.com.

  • Trigonographer at trigonography.com, spotlighting diagrammatic proofs for trig relations.

  • Hedronometer at hedronometry.com, studying the dimensionally-enhanced trig of tetrahedra.

  • I use GeoGebra —specifically, the desktop app— for my images.
Badges
View all badges
11
gold badges
117
silver badges
227
bronze badges
Top tags
View all tags
3,119
Score
834
Posts
59
Posts %
1,718
Score
313
Posts
22
Posts %
875
Score
242
Posts
17
Posts %
763
Score
177
Posts
13
Posts %
666
Score
113
Posts
8
Posts %
592
Score
151
Posts
11
Posts %
Top posts
View all questions and answers
All Questions Answers
Score Newest
answer
155
How can I understand and prove the "sum and difference formulas" in trigonometry?
Aug 1, 2010
answer
142
Why does factoring eliminate a hole in the limit?
Aug 8, 2013
answer
138
One question to know if the number is 1, 2 or 3
Oct 3, 2013
answer
106
A function in which addition and multiplication behave the same way
Sep 12, 2016
answer
99
Inscribing square in circle in just seven compass-and-straightedge steps
Dec 24, 2015
answer
95
How can we sum up $\sin$ and $\cos$ series when the angles are in arithmetic progression?
Jan 10, 2016
answer
73
Variation on Pythagoras: If $a^2 + b^2 = c^2$, then $a + b \leq c\sqrt{2}$
Jun 19, 2015
answer
70
How do you define functions for non-mathematicians?
Aug 6, 2010
answer
66
Alternative notation for exponents, logs and roots?
Feb 21, 2015
answer
60
Where does the $-2ab$ term come from in the cosine law?
Oct 22, 2017
Top Meta posts
0
7
6
Logo ideas/proposals
4
User flooding the site with questions - more than 6/day
4
User flooding the site with questions - more than 6/day
3
What domain name to use?
Top network posts
View all network posts
17
The 4th vertex of a triangle?
15
Pythagorean theorem for right-corner hyperbolic simplices?
15
Pointers for direct proof of extension of the Descartes Rule of Signs to complex polynomials?
10
Spectral graph theory: Interpretability of eigenvalues and -vectors
9
What are trig classes like within a universe that's "noticeably" hyperbolic?

Your privacy

By clicking “Accept all cookies”, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy.