http://www.mathopolis.com/questions/index.php

Can you do those?

]]>Neither did I. That is one book I do not have in my library.

]]>A picture is worth a thousand words and a video is a lot of pictures.

]]>I call the second one "the difference between two squares."

]]>Unfortunately, it is a UK company that does not ship to the US. But that is okay because I do not have the money right now anyway.

]]>This is not surprising because when we go along the cicumference say from P to P'

we encounter twice height of triangle and once side of a triangle. I had so much of trouble writing above in LATEX.

I've inserted spaces using space \ space. Bob Bundy.

]]>tan(36)

http://www.mathisfunforum.com/viewtopic … 87#p378587

The Regular Icosahedron

http://www.mathisfunforum.com/viewtopic.php?id=22966

Note: I was having difficulty making my answer match the one given by Monox D. I-Fly. I have worked out the two versions are the same but I cannot get the final proof to post; why I don't know. So I'll try again later

Base Vectors and Coordinates. A beginning.

http://www.mathisfunforum.com/viewtopic … 53#p387953

A matrix for rotation and the compound angle formulas

http://www.mathisfunforum.com/viewtopic … 28#p389628

Bob

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