TI Nspire graph Question
12-27-2019, 09:42 PM (This post was last modified: 12-27-2019 09:43 PM by ijabbott.)
Post: #2
 ijabbott Senior Member Posts: 870 Joined: Jul 2015
RE: TI Nspire graph Question
(12-27-2019 04:29 AM)lrdheat Wrote:  I have the Nspire CAS IPad app...when graphing 1/((tan 2*x)^(sin 2*x)), I get the expected real part of the graph, but, surprisingly, a messy mash of graphing where there is no real solution. Is this to be expected, or do I have some setting that needs to be changed?

If you change the Document Settings, Real or Complex setting to something other than "Real" (i.e., change it to either "Rectangular" or "Polar"), then the graph will only show the parts where the principal value is real.

In Real mode, it seems to treat the approximate value of (sin(2*x)) as a rational number and magics up a real result when (tan(2*x)) is negative. For example, when x is 1, so 2*x is 2, tan(2) is approx -2.1850398632615, sin(2) is approx 0.90929742682568, and (-2.1850398632615)^0.90929742682568 produces a real result of approx 2.03549259451, and 1/2.03549259451 is approx 0.491281571202, so the graph plots a point at (1, 0.491281571202) even though the principal value is complex.

In Rectangular mode, 1/((tan(2))^(sin(2))), approx 1/((-2.1850398632615)^0.90929742682568) produces a complex result of approx -0.471470916087-0.138104154488*i, so no point is plotted on the graph for x=1.

— Ian Abbott
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 Messages In This Thread TI Nspire graph Question - lrdheat - 12-27-2019, 04:29 AM RE: TI Nspire graph Question - ijabbott - 12-27-2019 09:42 PM RE: TI Nspire graph Question - lrdheat - 12-28-2019, 05:07 AM RE: TI Nspire graph Question - Joe Horn - 12-28-2019, 10:47 AM RE: TI Nspire graph Question - lrdheat - 12-28-2019, 03:44 PM RE: TI Nspire graph Question - lrdheat - 12-28-2019, 05:13 PM RE: TI Nspire graph Question - lrdheat - 12-30-2019, 10:00 PM RE: TI Nspire graph Question - ijabbott - 12-30-2019, 10:34 PM RE: TI Nspire graph Question - lrdheat - 12-30-2019, 10:49 PM RE: TI Nspire graph Question - ijabbott - 12-31-2019, 12:10 PM

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