Getting a 35S/33S to behave
04-24-2014, 06:02 PM (This post was last modified: 04-24-2014 06:05 PM by Matt Agajanian.)
Post: #1
 Matt Agajanian Senior Member Posts: 544 Joined: Dec 2013
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?
04-24-2014, 06:08 PM
Post: #2
 r. pienne Member Posts: 53 Joined: Dec 2013
RE: Getting a 35S/33S to behave
Try it and see.
04-24-2014, 06:15 PM
Post: #3
 Matt Agajanian Senior Member Posts: 544 Joined: Dec 2013
RE: Getting a 35S/33S to behave
Okie doke.
04-24-2014, 07:30 PM
Post: #4
 Thomas Klemm Senior Member Posts: 1,447 Joined: Dec 2013
RE: Getting a 35S/33S to behave
(04-24-2014 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 $$\sin(x)=\cos(90-x)$$ and $$\tan(x)=\frac{1}{\tan(90-x)}$$.

Probably not. Replace $$90$$ by $$\frac{\pi}{2}$$ in the formulas above when using radians mode.

Cheers
Thomas
04-24-2014, 07:32 PM
Post: #5
 Matt Agajanian Senior Member Posts: 544 Joined: Dec 2013
RE: Getting a 35S/33S to behave
(04-24-2014 07:30 PM)Thomas Klemm Wrote:
(04-24-2014 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 $$\sin(x)=\cos(90-x)$$ and $$\tan(x)=\frac{1}{\tan(90-x)}$$.

Probably not. Replace $$90$$ by $$\frac{\pi}{2}$$ in the formulas above when using radians mode.

Cheers
Thomas

Thanks! Those are normalisation techniques I can live with.
04-24-2014, 10:05 PM
Post: #6
 Matt Agajanian Senior Member Posts: 544 Joined: Dec 2013
RE: Getting a 35S/33S to behave
Okay here's a test:

So, what's the verdict?
04-25-2014, 12:54 AM
Post: #7
 Thomas Klemm Senior Member Posts: 1,447 Joined: Dec 2013
RE: Getting a 35S/33S to behave
(04-24-2014 10:05 PM)Matt Agajanian Wrote:  Okay here's a test:

As the HP-11C 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.

So, what's the verdict?

It appears there's a problem with small values as well.
Quote:105 * sin(0.0001)

HP-32SII 9.99999998333
HP-33S 9.99999998300
actual 9.99999998333

You could try another identity: $$\sin(x)=2\sin(\frac{x}{2})\cos(\frac{x}{2})$$.
Code:
2 / 1 ->R * 2 *
Don't search too long for ->R on the HP-35S.

Cheers
Thomas
 « Next Oldest | Next Newest »

User(s) browsing this thread: 1 Guest(s)