Question
Question: If \|z – 2 – i\| = \|z\| sin \(\left( \frac{\pi}{4} - \arg z \right)\) then locus of z is/ are...
If |z – 2 – i| = |z| sin (4π−argz) then locus of z is/ are
A
Ellipse
B
Circle
C
Parabola
D
Pair of straight lines
Answer
Parabola
Explanation
Solution
Sol. |(x – 2) + i (y – 1)| = |z| (21cosθ−21sinθ)
q = arg z
Ž (x−2)2+(y−1)2
= 21|z| cos q – 21 |z| sin q
= 21 (x – y)
Ž parabola with vertex (2, 1)
directrix x – y = 0