Timeline for Connecting tangents of convex curves: at some point orthogonal?

7 events

when toggle format	what		by	license	comment
Jan 21, 2012 at 15:58	history	edited	Anton Petrunin	CC BY-SA 3.0	edited body
Jan 21, 2012 at 14:58	comment	added	Tapio Rajala		A confusion might arise from "not concentric circles" as Anton meant here "If $a$ and $b$ are non-concentric circles then you get only these two values".
Jan 21, 2012 at 14:49	comment	added	Anton Petrunin		Take two circles, say $a(t)=(1+\cos t,\sin t)$ and $b(t)=10{\cdot}(\cos t,\sin t)$. Then $\theta(t)=\tfrac\pi2$ iff $t=0$ or $\pi \pmod {2{\cdot}\pi}$.
Jan 21, 2012 at 14:09	comment	added	Joseph O'Rourke		@Anton: However, note there are four spots in my posted example at which $\theta(t)=\pi/2$. Not sure what you mean by "then you get only these two values."
Jan 21, 2012 at 13:36	vote	accept	Joseph O'Rourke
Jan 21, 2012 at 3:54	history	edited	Anton Petrunin	CC BY-SA 3.0	added 83 characters in body
Jan 21, 2012 at 3:47	history	answered	Anton Petrunin	CC BY-SA 3.0