Let the given line intersect x-axis at R. If a line through R intersects the hyperbola at S and T, then the minimum value of (RS) (RT) is ________
8
Locus of circum centre is rectangular hyperbola.
R = (2, 0) Any point through R is (2 + r cosθ, r sin θ)
⇒ (2 + r cos θ ) (r sin θ ) = 4
⇒ r2 sin θ cos θ + 2 r sin θ = 4
∴r1r2 =∣∣4sinθcosθ∣∣≥8