Timeline for Zeroes of trigonometric-like function

9 events

when toggle format	what		by	license	comment
May 13, 2016 at 18:12	vote	accept	Sergei
May 13, 2016 at 18:12	vote	accept	Sergei
May 13, 2016 at 18:12
May 13, 2016 at 15:58	comment	added	Sergei		sorry I was not accurate with scales.
May 13, 2016 at 15:32	comment	added	Robert Israel		The point at bottom left is $(a = 0.2, b =1)$, for which there is a zero at approximately $.151056658766346+1.76010715962816 i$.
May 13, 2016 at 15:21	comment	added	Robert Israel		No, my plot does not have a point at $(1,1)$.
May 13, 2016 at 5:43	comment	added	Sergei		thank you. Note on your graph for a point (1,1) it seems there are complex zeroes not on the cross of axes. But the next command in MATHEMATICA $NSolve[Cosh[z] Cos[z] + Sinh[z] Sin[z] == 0 && -100 <= Re[z] <= 100 && -100 <= Im[z] <= 100, z]$ gives all zeroes on the cross.
May 12, 2016 at 20:18	history	edited	Robert Israel	CC BY-SA 3.0	added 650 characters in body
May 12, 2016 at 4:19	comment	added	Sergei		thank you for useful calculations. It is quiet possible that mine calculations were not accurate, I am not very good in them. But may you to plot $D$ in $(a,b)$ - plane approximately? And to prove strictly that $D$ is unbounded is also an interesting problem , not so?
May 11, 2016 at 21:09	history	answered	Robert Israel	CC BY-SA 3.0