regarding result form : abs value of complex number
08-25-2015, 02:43 AM (This post was last modified: 08-25-2015 02:57 AM by aiden.)
Post: #1
 aiden Junior Member Posts: 4 Joined: Aug 2015
regarding result form : abs value of complex number
Hi I'm newbie Hp prime.
I have a question about result form such as the abs value of complex number. Let me give a simple example for your understanding.

Q. abs of (1-i*x)/(1+i*x) ? where i is imaginary numbers.
Please see comparison results i attached.
On left, it gives very complex result using IM(x), RE(x) so on
On right, it gives simple answer i expected.

And, in case of TI nspire, it returns '1' as answer.

Attached File(s) Thumbnail(s)

08-25-2015, 02:56 AM
Post: #2
 Joe Horn Senior Member Posts: 2,005 Joined: Dec 2013
RE: Complex number absolute value
(08-25-2015 02:43 AM)aiden Wrote:  I don't know why they give different answers Please help me out to understand this situation and give the way to transfer complex answer to simple answer such as virtual calculator's or TI's.

You are getting different answers (hardware calculator versus emulator) because the CAS Settings are different. If you use the default settings (press Shift CAS, then Shift Esc, to get the default settings), and change the Simplify setting to Maximum, you will get 1 as desired. The result with the RE and IM terms in it was due to having the "Include complex results in variables" setting turned on (CAS Settings, 5th line, 2nd column), which means that the x in your expression can be complex, which is probably not what you need, so leave that setting turned off.

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-Joe-
08-25-2015, 02:59 AM
Post: #3
 aiden Junior Member Posts: 4 Joined: Aug 2015
RE: regarding result form : abs value of complex number
(08-25-2015 02:56 AM)Joe Horn Wrote:
(08-25-2015 02:43 AM)aiden Wrote:  I don't know why they give different answers Please help me out to understand this situation and give the way to transfer complex answer to simple answer such as virtual calculator's or TI's.

You are getting different answers (hardware calculator versus emulator) because the CAS Settings are different. If you use the default settings (press Shift CAS, then Shift Esc, to get the default settings), and change the Simplify setting to Maximum, you will get 1 as desired. The result with the RE and IM terms in it was due to having the "Include complex results in variables" setting turned on (CAS Settings, 5th line, 2nd column), which means that the x in your expression can be complex, which is probably not what you need, so leave that setting turned off.

Thank you so much!!!!!!!!!!!!!!!
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