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+--- 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)?
If you check manually, you will see that second result is correct if numbers are expected in radian: sin(rad(60))=-0,3048106211 and so on.
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)