Getting a 35S/33S to behave

04242014, 06:02 PM
(This post was last modified: 04242014 06:05 PM by Matt Agajanian.)
Post: #1




Getting a 35S/33S to behave
Hello all.
Let me cite the trig issue of the 33s/35s. Although trig operations near 90 degrees are a dud, is there a means to normalise a near 90 value so that a trig function can return an accurate result? Would converting the angle from degrees to radians/grads and calculating the trig function in radians/grads help? 

04242014, 06:08 PM
Post: #2




RE: Getting a 35S/33S to behave
Try it and see.


04242014, 06:15 PM
Post: #3




RE: Getting a 35S/33S to behave
Okie doke.


04242014, 07:30 PM
Post: #4




RE: Getting a 35S/33S to behave
(04242014 06:02 PM)Matt Agajanian Wrote: Although trig operations near 90 degrees are a dud, is there a means to normalise a near 90 value so that a trig function can return an accurate result?Use \(\sin(x)=\cos(90x)\) and \(\tan(x)=\frac{1}{\tan(90x)}\). Quote:Would converting the angle from degrees to radians/grads and calculating the trig function in radians/grads help?Probably not. Replace \(90\) by \(\frac{\pi}{2}\) in the formulas above when using radians mode. Cheers Thomas 

04242014, 07:32 PM
Post: #5




RE: Getting a 35S/33S to behave
(04242014 07:30 PM)Thomas Klemm Wrote:(04242014 06:02 PM)Matt Agajanian Wrote: Although trig operations near 90 degrees are a dud, is there a means to normalise a near 90 value so that a trig function can return an accurate result?Use \(\sin(x)=\cos(90x)\) and \(\tan(x)=\frac{1}{\tan(90x)}\). Thanks! Those are normalisation techniques I can live with. 

04242014, 10:05 PM
Post: #6




RE: Getting a 35S/33S to behave
Okay here's a test:
sin(1.566981956radians) and cos(0.003814371radians) yield 0.999992725295 on the 35S sin(1.5669819576radians) and cos(0.00381437113radians) yields 0.999992725295 on the 11C sin(1.5669819576radians) and cos(0.00381437113radians) yields 0.999992725303 on the 32SII sin(1.5669819576radians) and cos(0.00381437113radians) yields 0.999992725303 on the 42S So, what's the verdict? 

04252014, 12:54 AM
Post: #7




RE: Getting a 35S/33S to behave
(04242014 10:05 PM)Matt Agajanian Wrote: Okay here's a test:As the HP11C can only handle 10 digits I assume there's a typo. I get sin(1.566981956) = 0.9999927253. I might not get why you use different input for the 35S and the other models. Quote: sin(1.5669819576radians) and cos(0.00381437113radians) yields 0.999992725303 on the 32SII It appears there's a problem with small values as well. From a previous thread about the HP33S: Quote:10^{5} * sin(0.0001) You could try another identity: \(\sin(x)=2\sin(\frac{x}{2})\cos(\frac{x}{2})\). Code: 2 Cheers Thomas 

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