Question

A circle passes through the points A(1, 0), B(5, 0) and C(0, h). If $\angle ACB$ is maximum then

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

$(x^2+y^2-6x+5)+\lambda y=0$
If $\angle ACB$ is maximum. Then y-axis will be the tangent to the circle
$\Rightarrow y^2+\lambda y+5=0$
Discriminant = 0
${\lambda }^2-20=0$
$\lambda =\pm 2\sqrt{10}$