Bug in converting complex numbers? - Printable Version +- HP Forums ( https://www.hpmuseum.org/forum)+-- Forum: HP Calculators (and very old HP Computers) ( /forum-3.html)+--- Forum: HP Prime ( /forum-5.html)+--- Thread: Bug in converting complex numbers? ( /thread-10999.html) |

Bug in converting complex numbers? - blevita - 07-03-2018 08:01 AM
Hi I have tried to convert a complex number in the style of 100*exp(60 Deg) Usually they should be converted to something like: 100*(cos(60)+i*sin(60)) = 50+86.6*i But the Prime converts the expression 100*exp(60 Deg) to -95.24 - 30.48*i This is a strange behaviour to me. Do i have to enter the complex number in an other way? Or is this a software bug? Attached a picture Thank RE: Bug in converting complex numbers? - blevita - 07-03-2018 08:17 AM
I have tested this behaviour a little bit more. It looks like there is a serious bug in the Prime. If i extract the RE part within the CAS it gives me the correct value of 50. If i extract the exact same thing withing the Calculator it gives me -95. If i approx the value within the CAS, also the CAS fails to convert correctly! Take a look at the pictures. RE: Bug in converting complex numbers? - sasa - 07-03-2018 08:59 AM
I do not have a Prime, however, this sems to be a problem misrepresenting input is in degree or radian and further result representation. Do you have to set independently degree and radian for each calculator mode (HOME/CAS)? If you check manually, you will see that second result is correct if numbers are expected in radian: sin(60)=-0,3048106211 and so on. RE: Bug in converting complex numbers? - blevita - 07-03-2018 09:03 AM
(07-03-2018 08:59 AM)sasa Wrote: Do you have to set independently degree and radian for both calculator modes (HOME/CAS)? Ok interessting. I have set the CAS and calculator to Degrees. You can see this also on the top right corner where you see the green Dregree symbol. I have also swithed to radians without success. But you are right. If i enter radians, the answer is correct. Thanks for your quick response! RE: Bug in converting complex numbers? - sasa - 07-03-2018 09:11 AM
Notice that x in exp(x) is not expected to be an angle, thus you have to do conversion manually. RE: Bug in converting complex numbers? - Nigel (UK) - 07-04-2018 11:04 AM
In general, trig functions on the Prime interpret any complex number as being in radians. For example, in degrees mode sin(30) is 0.5, but sin (30+0*i) is -0.988, even when a degrees sign is added after the "30". I believe this is standard practice on calculators that support trig and exponential functions with complex arguments, so it should be viewed as a feature, not a bug! Nigel (UK) |