Re: History of trigonometry

About the interior vis-a-vis exterior angles, the interior angle of the
regular polygon, n-gon, with n > 3, is 2pi / n. At that vertex, the
interior angle's complement, the exterior angle, is 2pi - 2pi/n.
Summing that over the vertices, that is 2(n-1)pi. Is that not the
definition of interior and exterior angle?

Excuse me, I was incorrect about the interior and exterior angle. The
angle (congruent angles) of the triangles that meet at the center of
the regular polygon are 2pi/n, and the angles between a ray on a side
around the polygon and the next consecutive side are 2pi/n, the
interior angles as I was calling them are pi - 2pi/n, and exterior
angles pi + 2pi/n, radians.

If Riemann integration is of vertical rectangles, and
Lebesgue/Stieltjes horizontal, what's integration about the circle with
triangles? I think they're called methods of symmetry.

Ross

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