Question
Question: If z<sub>1</sub> = 8 + 4i, z<sub>2</sub> = 6 + 4i, and arg\(\left( \frac{z–z_{1}}{z–z_{2}} \right)\)...
If z1 = 8 + 4i, z2 = 6 + 4i, and arg(z–z2z–z1)= 4π, then z satisfies –
A
| z – 7 – 4i | = 1
B
| z – 7 – 5i | = 2
C
| z – 4i | = 8
D
| z – 7i| = 18
Answer
| z – 7 – 5i | = 2
Explanation
Solution
Sol. arg (z – z1) – arg (z – z2) = p/4
arg (x – 8 + i (y – 4)) – arg ((x – 6) + i (y – 4)) = p/4
tan–1(x–8y–4)– tan–1(x–6y–4)= 4π
̃ x2+y2–14x–8y+642(y–4)= 1
̃ x2 + y2 – 14x – 10 y + 72 = 0
̃ (x – 7)2 + (y – 5)2 = (2)2 ̃ | z – (7 + 5 i) | = 2