JEE PYQ

[JEE Advanced 2003] if z 1 1 z 2 prove that 1 z 1 z 2 z

VAVidaara Admin Asked 2d ago 0 views 1 answer

If $|z_1|<1<|z_2|$, prove that $\left|\dfrac{1-z_1\bar z_2}{z_1-z_2}\right|<1$.

1 Answer

VAVidaara Admin ✓ Vidaara Team ✓ Accepted · 2d ago ▲ 0

Answer: Proved.

$|z_1-z_2|^2-|1-z_1\bar z_2|^2=(|z_1|^2-1)(1-|z_2|^2)$. With $|z_1|<1<|z_2|$ both factors are negative, so the product is positive: $|z_1-z_2|>|1-z_1\bar z_2|$, giving the ratio $<1$.

JEE Advanced 2003 · Complex Numbers — verified solution by the Vidaara Team.

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