Cartesian Form of complex numbers
z = x + iy
Convert to modulus argument form
z = r(cos(theta) + i sin(theta))
where z = root(x^2 + y^2) and theta = tan^-1(y/x)
Complex conjugates
Roots come in conjugate pairs, represented as z*. This = x - iy
How to multiply complex numbers
Multiply mod, add arguments
How to divide complex numbers
Divide mod, subtract arguments
How to manipulate mod-arg form. cosx - isinx =
cos(-x) + isin(-x)
Perpendicular bisector of z1 and z2
|z-z1| = |z-z2|
Circle radius r centre z1
|z - z1| = r
Half line drawn from z1, angle x
arg(z-z1) = x