If two of the lines represented by the equation y³+axy²+(a²+6)x²y+2x³=0 are perpendicular to each other,then a is equal to

a.-2

b.-4

c.2

d.4

Hi Menka,

The system of lines passes through the origin (as is evident from the given eqn).

So use y=mx, you'd get a cubic in "m". For which m1,m2,m3 are the roots.

Find:

1) m1m2m3

2) m1m2 + m2m3 + m3m1

3) m1+m2+m3

from the equation, and use m1m2=-1.

And using this condition, elimintae m1,m2,m3 from the three equations, and find "a".

Best Regards,

Ashwin (IIT Madras)

dUDE QUESTION IS WRONG,PAIR OF LINES ARE OF 2 DEGREES .THIS CURVE DOES NOT REPRESENT 2 LINES.