cancel
Showing results for 
Search instead for 
Did you mean: 
The HP Calculator Community Message Board is moving. While we prepare for the move, we are unable to accept new postings. During the move, you can look for help from other users by visiting https://www.hpmuseum.org/ . Or if you need technical support for your calculator visit: HP Calculators. .
ArchivedThis topic has been archived. Information and links in this thread may no longer be available or relevant. If you have a question create a new topic by clicking here and select the appropriate board.
BartdB
Level 9
971 905 119 118
Message 1 of 11
2,046
Flag Post

HP 39gII BUG: complex numbers and powers

HP Recommended

Thr following:

 

(0.02+0.01*i)^3  results in:

 

1.14486680448E−11+6.29676742464E−11*i

 

the correct answer is:

 

.000002+.000011*i

 

the correct answer can be obtained by entering (0.02+0.01*i)*(0.02+0.01*i)*(0.02+0.01*i).

 

Firmware version: 30/Oct/2013 Rev: 19148

 

 

I found this while using the calculator at work. I had put it aside due to previous frustrations, but this past week I decided to use it again - and very soon I run into a problem.

 

This calculator has been for sale for almost two years. The last update was more than 6 months ago. It still has serious bugs. Is this becoming the forgotten brother of the Prime?

 

Whenever I complain about the 39gii, I get reminded that other HP calulators e.g. 48GX also had bugs, but these have never affected me in daily work!

 

Unfortunately I am losing my faith in the current development team.

 

-Bart
_________________________________________________________
calculator enthusiast
10 REPLIES 10
Mmmm--
Level 1
11 8 0 0
Message 2 of 11
Flag Post
HP Recommended

Even weirder :

 

(0.02+0.01i)^1 = 0.0003577708764+0.0001788854382i

 

 

the ^ must be doing something other than raising to a power....

Was this reply helpful? Yes No
BartdB
Author
Level 9
971 905 119 118
Message 3 of 11
Flag Post
HP Recommended

Further to this:

 

Using the x² function gives correct answer, using ^2 "to power of 2" gives erroneous answer.

 

Also when using larger numbers correct answers result, e.g.:

(2.15+1.25*i)^3  results in correct answer of −.13975+15.38125*i

 

 

-Bart
_________________________________________________________
calculator enthusiast
Was this reply helpful? Yes No
Mmmm--
Level 1
11 8 0 0
Message 4 of 11
Flag Post
HP Recommended

It looks to me to be the case that as long as one of |a| or |b| is greater than 1 (not equal) in a+bi you'll get the correct answer when raising it to a power.The closer to zero the maximum of a and b is, the bigger the error!.

 

 

 

 

Was this reply helpful? Yes No
BartdB
Author
Level 9
971 905 119 118
Message 5 of 11
Flag Post
HP Recommended

Mmmm-- wrote:

It looks to me to be the case that as long as one of |a| or |b| is greater than 1 (not equal) in a+bi you'll get the correct answer when raising it to a power.The closer to zero the maximum of a and b is, the bigger the error!.



Unfortunately the numbers I use are not limited to the "good" range. :smileysad:

-Bart
_________________________________________________________
calculator enthusiast
Was this reply helpful? Yes No
Mmmm--
Level 1
11 8 0 0
Message 6 of 11
Flag Post
HP Recommended

(2+i)^3/100^3 works, (just to get the a>1). 

 

But really that is just ridiculous!

Was this reply helpful? Yes No
BartdB
Author
Level 9
971 905 119 118
Message 7 of 11
Flag Post
HP Recommended

So, more than a year after posting this and still no update in sight!

 

Apparently it is a faulty implementation of LN for complex arguments.

http://www.hpmuseum.org/forum/thread-3750-post-34071.html#pid34249

 

Indeed try:

LN(0.01+0.01i)

 

HP-39gii answer: -9.210340+0.785398i

 

Correct answer: -4.258597+0.785398i

 

Bah humbug.

-Bart
_________________________________________________________
calculator enthusiast
Was this reply helpful? Yes No
Maké
Level 9
3,551 3,055 180 330
Message 8 of 11
Flag Post
HP Recommended

Hi!, Mnnn:

 

See this document, with version 19157, for Connectivity Kit, in HP39GII ... https://tiplanet.org/forum/viewtopic.php?t=13482&p=153154#p153154

Kind Regards !.
Have a nice day !.
@Maké (Technical Advisor Premium - HP Program Top Contributor).
Provost in HP Spanish Public Forum ... https://h30467.www3.hp.com/
Was this reply helpful? Yes No
BartdB
Author
Level 9
971 905 119 118
Message 9 of 11
Flag Post
HP Recommended

 

Thank you for the link, however that is the exact same version that I have and that has the bug.

 


@Maké wrote:

Hi!, Mnnn:

 

See this document, with version 19157, for Connectivity Kit, in HP39GII ... https://tiplanet.org/forum/viewtopic.php?t=13482&p=153154#p153154


 

-Bart
_________________________________________________________
calculator enthusiast
Was this reply helpful? Yes No
Fortin
Level 4
127 110 14 16
Message 10 of 11
Flag Post
HP Recommended

For what it's worth, the Prime gives correct answers to your examples.  😕

Was this reply helpful? Yes No
ArchivedThis topic has been archived. Information and links in this thread may no longer be available or relevant. If you have a question create a new topic by clicking here and select the appropriate board.
† The opinions expressed above are the personal opinions of the authors, not of HP. By using this site, you accept the Terms of Use and Rules of Participation