Math Is Fun Forum

Daniel123

Member

Registered: 2007-05-23

Posts: 663

Complex Loci

I'm trying to follow a solution to a question given in my textbook, but I can't see how they're doing it. I can get to the answer myself, but my way is fiddly and annoying, so I'm wondering how they're doing it:

Solution:

To find the circle, we determine the two points at which it intersects the line joining z_1 to z_2, where z_1 = 18 and z_2 = -18i.

The two points satisfying the locus are 6 - 12i and -18 - 36i (where do they get this from?)

The rest of the solution is fine, I just don't know how they get the above.

Thanks.

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Complex Loci

I would do it like this: put

.

Then

Daniel123

Member

Registered: 2007-05-23

Posts: 663

Re: Complex Loci

Ok that's much better. I was trying to do it geometrically. Thanks Jane.