What is the locus of z, if amplitude of z – 2 – 3i is π/4 ?
Let z = x + iy. Then z – 2 – 3i = (x – 2) + i (y – 3)
Let θ be the amplitude of z – 2 – 3i. Then tanθ = (y-3)/(x-2)
⇒ tan π/4 = (y-3)/(x-2) [since θ=π/4 ]
⇒ 1 = (y-3)/(x-2) i.e. x – y + 1 = 0
Hence, the locus of z is a straight line.