Question
Question: If z = (a + 3) + i \(\sqrt{5 - \alpha^{2}}\), then the locus of z is...
If z = (a + 3) + i 5−α2, then the locus of z is
A
An ellipse
B
A circle
C
A parabola
D
A straight line
Answer
A circle
Explanation
Solution
Sol. Let z = x + iy
z = a + 3 + i(5−α2)
x + iy = a + 3 + i(5−α2)
x = a + 3
y = (5−α2)
y = 5−(x−3)2 Ž y2 = 5 – x2 – 9 + 6x
x2 + y2 – 6x + 4 = 0 (focus is circle)