What is the difference between 25i*20i/5i and 25i*20i/(5i) in CMPLX mode?

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Homework Help Overview

The discussion revolves around the interpretation of two mathematical expressions involving complex numbers in CMPLX mode on a calculator. The original poster presents a confusion regarding the results of the expressions 25i*20i/5i and 25i*20i/(5i), where i represents the imaginary unit.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the differences in interpretation of the expressions based on order of operations and the placement of parentheses. There is a focus on how the calculator evaluates these expressions differently.

Discussion Status

Participants have provided insights into the interpretation of the expressions, noting the importance of parentheses to clarify the intended calculations. There is an ongoing exploration of how complex numbers are treated in these contexts, but no consensus has been reached on a definitive resolution.

Contextual Notes

Some participants mention the need for clarity in expression evaluation to avoid ambiguity, suggesting that the original poster consider using parentheses in future calculations.

Nero26
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Hi all,
This is a little problem I'm unable to figure out, in CMPLX mode of my calculator 25i*20i/5i=-100i
But 25i*20i/(5i) = 100i, Here i=sqrt(-1). What is the difference between these two expressions?
Thanks for your help.
 
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The difference is that 25i*20i/5i is interpreted as (25i*20i/5)i = (25i*20i/5)*i.
And 25i*20i/5 = -100.
 
CompuChip said:
The difference is that 25i*20i/5i is interpreted as (25i*20i/5)i = (25i*20i/5)*i.
And 25i*20i/5 = -100.

Thanks a lot for your help, so 'i' is considered as a single complex number.
 
Nero26 said:
Thanks a lot for your help, so 'i' is considered as a single complex number.
Well, yes, but that's not relevant here.

What Compuchip was talking about was the order of operations. It's the difference between -500/(5i) and (-500/5) * i.

When you write (or enter) -500/5i, the calculator is interpreting this as -500/5 * i.
 
In order to avoid ambiguity in expression evaluation, use parentheses in your expressions.
 
Thanks to all. You all are of great help. I think I can learn a lot from PF.
 

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