If ax+y=1 intersects the curve 5x²-15y²+3xy+5=0 in A and B and AB subtends 90° at origin then a² is equal to

a.-5

b.-1

c.1

d.3

Hi Menka,

This question is related to homogenising of a 2nd Degree Eqn, with respect to a line.

The homogenised eqn, would represent a pair of St Lines through the origin.

For them to subtend 90° at the origin, (co-eff of x^2)+(co-eff of y^2) in the homogenised eqn = 0.

And hence you will get "a" value.

Best Regards,

Ashwin (IIT Madras).