The straight line is

The Cartesian equations of a lines are What is its vector equation?

The angle between two lines having direction ratios 1, 1, 2 and 4 is

If a line makes angles α, β and γ with the x-axis, y-axis and z-axis respectively then (sin² α + sin² β + sin² γ) = ?

If (a₁, b₁, c₁) and (a₂, b₂, c₂) be the direction ratios of two parallel lines then