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Mathematics 9 Online
OpenStudy (itiaax):

PLEASE HELP. Complex numbers. *question attached below* Will give medal and fan :)

OpenStudy (itiaax):

I'm pretty much stuck on this problem :( Can I have some help, please?

OpenStudy (anonymous):

yes

OpenStudy (anonymous):

nope

ganeshie8 (ganeshie8):

Notice that reducing the imaginary component by 1 unit is giving the same length as reducing the real component by 1 unit

ganeshie8 (ganeshie8):

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ganeshie8 (ganeshie8):

Can we say the locus of z has to be that straight line through origin ?

OpenStudy (itiaax):

How do we know it passes through the origin? :S

ganeshie8 (ganeshie8):

plugin z = 0+0i in the given equation

OpenStudy (itiaax):

Oooh, but aren't we supposed to plug in z=x+iy instead of 0+0i?

ganeshie8 (ganeshie8):

Ahh that works too but I thought this is easy to figure out with geometry argument, lets solve it algebraically now :)

ganeshie8 (ganeshie8):

|z-i| = |z-1| |x+i(y-1)| = |(x-1) + iy| x^2 + (y-1)^2 = (x-1)^2 + y^2 simplify

OpenStudy (itiaax):

x^2+y^2-2y+1 = x^2-2x+1+y^2

OpenStudy (itiaax):

So we end up with 2x-2y=0?

ganeshie8 (ganeshie8):

yes cancel 2 and you would get y=x

OpenStudy (itiaax):

Yes :)

OpenStudy (itiaax):

Do we do the same thing for |w-4|=2 now?

ganeshie8 (ganeshie8):

we caan, but again doesn't that equation look closely related to r = 2 ?

ganeshie8 (ganeshie8):

it seems the center got shifted right by 4 units, otherwise it should give a circle of radius 2 units eh ?

OpenStudy (itiaax):

Oh yes

OpenStudy (itiaax):

So on the Argand diagram, do we have a straight line and a circle, then?

ganeshie8 (ganeshie8):

yes draw them

OpenStudy (itiaax):

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