Math Is Fun Forum

tripled2006

Member

Registered: 2006-12-07

Posts: 1

representing complex numbers in polar form

Hi all,

I am wondering about how to convert a complex number into polar form. I know how to convert it into the polar form representation which is r(cos (theta) + isin (theta));
                                                                                                                                                                         ______
But I have a question that asks me, for example, to express 3-2i in polar form (this type of polar form representation x| y °    .

Has anyone seen this kind of polar form representation before, and if so, how do you do this problem. Also, how would you go backwards from the polar form representation above to the complex number in the form a+bi ?

Thank you to everyone in advance who read and/or replied to this problem.

Dan.

LQ

Real Member

Registered: 2006-12-04

Posts: 1,285

Re: representing complex numbers in polar form

Wow, you got me thinking there!

r^2 = x^2 + y^2 = 3^2 + 2^2 = 13

Treat  r, x and y as the sides of a triangle, r being hypothenus or whatever you want to call it.

tan-1(y/x) = v

sin(v) = y/r
cos(v) = x/r

r(cos(v)+isin(v)) = 3 - 2i

That is how I would do it. But I'm a little ringrusty. Sorry about that.

Last edited by LQ (2006-12-07 06:48:09)

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