Modulus of a Complex Number Question

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SUMMARY

The modulus of a complex number is not simply the absolute value; it represents the distance from the origin in the complex plane. The equation |z-1+i|=1 describes a circle centered at the point (1, -1) with a radius of 1. By substituting z = x + iy, the equation simplifies to (x-1)² + (y+1)² = 1, confirming that the graph is indeed a circle, not just two points. This understanding is crucial for accurately interpreting complex number equations in graphical form.

PREREQUISITES
  • Understanding of complex numbers and their representation in the Argand diagram.
  • Familiarity with the concept of modulus in complex analysis.
  • Basic knowledge of Cartesian coordinates and equations of circles.
  • Ability to manipulate algebraic expressions involving complex variables.
NEXT STEPS
  • Study the properties of complex numbers, focusing on modulus and argument.
  • Learn how to graph complex functions on the Argand diagram.
  • Explore the geometric interpretations of complex number equations.
  • Investigate transformations of complex numbers and their effects on graphical representations.
USEFUL FOR

Students studying complex analysis, mathematics educators, and anyone interested in understanding the geometric properties of complex numbers.

tylerc1991
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Homework Statement



My prof was saying today that the modulus of a complex number isn't the absolute value. The problem is the following:

Graph the set of points satisfying the following equation(s):

|z-1+i|=1

The Attempt at a Solution



Can I not just say that z = -i or z = 2-i and hence the graph is just two points? Or is this the correct answer?
 
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If you plot |z-1+i|=1 on an argand digram, you will see that this does not give only two solutions. If you put z=x+iy into the equation and then find the modulus knowing that |a+ib|=√(a2+b2), what do you get?
 
I see what I did wrong now. If I let z = x + iy I am getting:

(x-1)^2 + (y+1)^2 = 1, which is obviously a circle.

Thanks!
 

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