Determining graphical set of solutions for complex numbers

AI Thread Summary
The discussion focuses on solving the inequality |(z+i)/z| < 1 and representing its solutions graphically on a coordinate system. Participants clarify that this can be rewritten as |z+i| < |z|, which represents the distance between the complex number z and -i compared to the distance from z to the origin. Geogebra is suggested as a useful tool for visualizing complex numbers, although one user expresses difficulty in using it for this purpose. Ultimately, the user reports successfully solving the problem after receiving guidance. The conversation highlights the importance of understanding geometric interpretations in complex number equations.
TheChemist_
Messages
22
Reaction score
1

Homework Statement


So we have been doing complex numbers for about 2 weeks and there is this one equation I just can't solve.
It's about showing the set of solutions in graphical form (on "coordinate" system with the imaginary and the real axis). So here is the equation:

Homework Equations


|(z+i)/z| < 1

The Attempt at a Solution


Well, I just don't know how to solve this "thing":biggrin:
The only thing we did was to picture some other solutions...

I hope you can help me with this little problem!
Thx
 
Physics news on Phys.org
TheChemist_ said:

Homework Statement


So we have been doing complex numbers for about 2 weeks and there is this one equation I just can't solve.
It's about showing the set of solutions in graphical form (on "coordinate" system with the imaginary and the real axis). So here is the equation:

Homework Equations


|(z+i)/z| < 1

The Attempt at a Solution


Well, I just don't know how to solve this "thing":biggrin:
The only thing we did was to picture some other solutions...

I hope you can help me with this little problem!
Thx

Write it as ##|z+i| < |z|##.

What are the graphical/geometric interpretations of the quantities ##|z+i|## and ##|z|##?
 
  • Like
Likes Mark44
Checkout Geogebra, its an educational software tool for students and it may be able to help you learn more about complex numbers.

https://www.geogebra.org/
 
jedishrfu said:
Checkout Geogebra, its an educational software tool for students and it may be able to help you learn more about complex numbers.

https://www.geogebra.org/

yeah I know geogebra and I use it quite often, but I haven't been able to figure out how I can view complex numbers...
 
Ray Vickson said:
Write it as ##|z+i| < |z|##.

What are the graphical/geometric interpretations of the quantities ##|z+i|## and ##|z|##?

Ok that made things a little clearer...but i still can't figure out how |z+i| could look...
 
TheChemist_ said:
Ok that made things a little clearer...but i still can't figure out how |z+i| could look...
|z + i| is the same as |z - (-i)|; i.e. the distance between a complex number z and the imaginary number -i. |z| represents the distance from the same z to the origin.
Edit: Fixed typo pointed out by SammyS.
 
Last edited:
Ok thanks guys I managed to solve it!
 
SammyS said:
Typo:
Thanks, SammyS. -i was what I meant. It's fixed in my earlier post now.
 
Back
Top