The Angle Between The Pair Of Lines Represented By 2x2 – 7xy + 3y2 = 0, Is     

If the slope of one of the lines given by ax² + 2hxy + by² = 0 is 5 times the other, then

If the pair of lines ax² + 2hxy + by² = 0 and a’x² + 2h’xy + b’y² = 0 have one line in common, then (ab’ – a’b)² =

If one of the lines given by ax² + 2hxy + by² = 0 may be perpendicular to one of the lines given by a’x² + 2h’xy + b’y² = 0, then (aa’ – bb’)² =

If the slope of one of the lines represented by ax² + 2hxy + by² = 0 be the square of the other, then   

The combined equation of the images of the pair of lines given by ax² + 2hxy + by² = 0 in the line mirror y = 0, is   

The difference of the tangents of the angles which the lines  make with X-axis, is 

The product of perpendiculars let fall from the point (x₁, y₁) upon the lines represented by ax² + 2hxy + by², is

The angle between the The Pair of Straight Lines

The pair of lines represented by 3ax² + 5xy + (a² – 2)y² = 0 are perpendicular to each other for 

The angle between the lines represented by , is