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subsets of C

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enpassant:
Find the cartesian equations for (i) |z+i|+|z-i|=1 and (ii) |z+i|-|z-i|=3. :idiot2:

ed_saifa:
let z= x + yi

Toothpaste:
(i)


Substitute z = x+yi into your equation:


Group like terms:




Bring one of the square roots over to the right hand side.


Square both sides - "undo the square roots"


 ... Quadratic expansion on the RHS by the way.


Move it around. Expand and






Square both sides.


Expand.


Expand .






Divide through by 3 to get 1 on the RHS.




See coblin's post for domain.
can't exist because Ahmad says so.






(ii) I didn't show all the steps for this one because when you get the hang of it you'll be able to get to the answer faster.

enpassant:
Not making sense!

Toothpaste:

--- Quote from: enpassant on March 30, 2008, 10:45:37 pm ---Not making sense!

--- End quote ---

All of it, or certain bits?

I'll put in annotations to show you what I did.

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