Why Does Arg(z) of a Complex Number Differ in Solutions?

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Homework Help Overview

The discussion revolves around the argument of a complex number expressed in polar form, specifically for the complex number (1/√2) - (i/√2). Participants are examining the differences in the calculated arguments and their representation in different quadrants.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are attempting to calculate the argument of the complex number and are questioning the validity of their results. There is a discussion about the equivalence of angles in different forms, such as 5π/4 and -3π/4, and whether the principal argument is being considered.

Discussion Status

The discussion is ongoing, with participants exploring the reasoning behind the different representations of the argument. Some guidance is provided regarding the definition of the principal argument, but no consensus has been reached on the correctness of the initial calculations.

Contextual Notes

There is a mention of the principal argument being defined within the range of (-π, π], which may influence the interpretation of the results. Participants are also reflecting on the quadrant placement of the angles involved.

charmedbeauty
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Homework Statement



express the arg(z) and polar form of

(1/\sqrt{2}) - (i/\sqrt{2})


Homework Equations





The Attempt at a Solution



Ok so I did \sqrt{(1/\sqrt{2})^{2}+(1/\sqrt{2})^{2}} = 1

so tan^{-1}(1) = \pi/4 so arg(z)=5\pi/4

but they had the answer as -3\pi/4

Am I wrong or are they because shouldn't the arg(z) lie in the third quad.??
 
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A better question for you is why do those numbers represent the same angle
 
Both 5\pi/4 and -3\pi/4 are in the third quadrant.
 
charmedbeauty said:

Homework Statement



express the arg(z) and polar form of

(1/\sqrt{2}) - (i/\sqrt{2})


Homework Equations





The Attempt at a Solution



Ok so I did \sqrt{(1/\sqrt{2})^{2}+(1/\sqrt{2})^{2}} = 1

so tan^{-1}(1) = \pi/4 so arg(z)=5\pi/4

but they had the answer as -3\pi/4

Am I wrong or are they because shouldn't the arg(z) lie in the third quad.??

Were they asking for the principal argument? i.e. Arg(z)? Arg(z) is defined to be in the range of (-\pi,\pi]
 

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