Complex line equation with condition |a| = |b|

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PcumP_Ravenclaw
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Dear All,
Please help me clear some doubts about Theorem 3.3.1 in the 1st attachment.
The condition ## |a| = |b| ## has only 8 cases right? ## { x+iy. x - iy, -x + iy, -x - iy, y + ix, y - ix, -y + ix, -y - ix } ##

so for the condition ## |a| = |b| ## and ## b \bar c = \bar a c ## in (2) and (3) in the attachement, what must ##b## and ##\bar a## be for them to to satisfy this equation given that C is a complex number of the form ## Cx + iCy ##.

why is there a line of solutions in (3)? usually you only get one imaginary and one real value for z right??

In the 2nd attachement, I have tried to do question 3. what does in the direction of b mean? does it pass through b also?? c =0 right? can you please give examples of the complex number b?

Danke...
 
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  • Printed text of Theorem 3.3.1 on complex equations az + b̄z̄ + c = 0, with three numbered cases: (1) a unique solution iff |a| ≠ |b|; (2) no solution iff |a| = |b| and b̄c ≠ āc; (3) a line of solutions iff |a| = |b| and b̄c = āc.
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  • Handwritten-style printed text, exercise 3: Suppose that b ≠ 0. Show that the equation of the line that passes through the origin in the direction b is b̄z = b z̄. What is the line b̄z = −b z̄?
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Last edited:
PcumP_Ravenclaw said:
Dear All,
Please help me clear some doubts about Theorem 3.3.1 in the 1st attachment.
The condition ## |a| = |b| ## has only 8 cases right? ## { x+iy. x - iy, -x + iy, -x - iy, y + ix, y - ix, -y + ix, -y - ix } ##
No, and how are x + iy, x - iy, etc. conditions? These are complex numbers. I don't see that they are conditions in any way. For example, consider a = 0 + 1i and b = -1/2 + (√3/2)i. These two complex numbers have the same magnitude, but I don't see how they are included in your eight cases, whatever it is you mean by them.

PcumP_Ravenclaw said:
so for the condition ## |a| = |b| ## and ## b \bar c = \bar a c ## in (2) and (3) in the attachement, what must ##b## and ##\bar a## be for them to to satisfy this equation given that C is a complex number of the form ## Cx + iCy ##.

why is there a line of solutions in (3)? usually you only get one imaginary and one real value for z right??

In the 2nd attachement, I have tried to do question 3. what does in the direction of b mean?
b is a complex number, so you can think of it as being a vector, with its tail at the origin and its head at the point in the complex point (b1, b2). What direction does it point?
PcumP_Ravenclaw said:
does it pass through b also?? c =0 right? can you please give examples of the complex number b?

Danke...
 
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