Question

The straight lines represented by the equation $a{x}^2+2bxy+b{y}^2=0$ are perpendicular if

• A. a-b = 0
• B. a+b = 0
• C. a+2h+b = 0
• D. a = 2h

Answer 1

The correct option is B

a+b = 0

The angle between the straight lines $a{x}^2+2bxy+b{y}^2=0$ is given by

$\tan \theta =\left|\frac{2\sqrt{h^2-ab}}{a+b}\right|$

They will be perpendicular if a+b = 0