If \(z_1\) and \(z_2\) are two complex numbers such that
\[
|z_1-a|=|z_2-a|
\]
for \(a\in\mathbb R\), and
\[
Arg(z_1-a)+Arg(z_2-a)=\frac{\pi}{2},
\]
then
\[
\frac{z_1-a}{z_2-a}=
\]
Show Hint
For complex numbers written as \(re^{i\theta}\), division preserves modulus ratio and subtracts arguments.