Inequalities of negative arguments in complex numbers

AI Thread Summary
The discussion centers on understanding the inequality Arg z ≤ -π/4 in the context of complex numbers. Participants clarify that the approach to arguments is consistent with negative numbers, emphasizing that the solution is an interval rather than a single value. It is noted that 60° is not a valid answer since it is a positive angle, and confusion arises regarding the conversion between radians and degrees. The importance of defining the range for the argument, either in [0, 2π] or [-π, π], is highlighted as crucial for solving the problem correctly. Overall, the conversation aims to clarify how to interpret and solve inequalities involving complex number arguments.
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Homework Statement


Arg z≤ -π /4

Homework Equations

The Attempt at a Solution


I'm confused whether the answer to that would be more than -45° or less. Should the approach to arguments be the same as in negative numbers?
 
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toforfiltum said:

Homework Statement


Arg z≤ -π /4

Homework Equations


3. The Attempt at a Solution [/B]
I'm confused whether the answer to that would be more than -45° or less. Should the approach to arguments be the same as in negative numbers?
The problem is the same whether stated in degrees or in radians.

Yes, the approach is the same as for negative numbers.

Regardless of the signs of two numbers, a < b means that b - a is positive.
 
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SammyS said:
The problem is the same whether stated in degrees or in radians.

Yes, the approach is the same as for negative numbers.

Regardless of the signs of two numbers, a < b means that b - a is positive.
Thanks! To confirm, the answer would be 60°...etc?
 
toforfiltum said:
Thanks! To confirm, the answer would be 60°...etc?
?
60° is a positive angle. Do you know how to convert from radians to degrees? Your answer above suggests that you don't.
The answer would not be a single number. It would be an interval of numbers, all of which are less than ##-\pi/4##.
 
toforfiltum said:
Thanks! To confirm, the answer would be 60°...etc?
Is it true that 60° ≤ -45° ?
 
Maybe you are confused with the fact that the argument is defined modulo two pi ?
 
toforfiltum said:

Homework Statement


Arg z≤ -π /4

Homework Equations

The Attempt at a Solution


I'm confused whether the answer to that would be more than -45° or less. Should the approach to arguments be the same as in negative numbers?

You need to decide whether you are taking ##\arg \, z ## in ##[0, 2\pi]## in ##[-\pi, \pi]##.
 

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