JEE Mains Model Paper 13

Put Tan−1x = α , Tan−1y = β Tan α = x ; Tan β = y
So given system of equations is
a tan α + b sec α = C ; a tan β + b sec β = C
∴ α , β are the roots of a tan θ + b sec θ = C
∴ Tan α + Tan β =

2ac

a2−b2

; tan α + tan β =

c2−b2

a2−b2

⇒

x+y

1−xy

=

2ac

a2−c2