Direction of Cosines and Direction Ratios
Direction of Cosines and Direction Ratios Theorem: If l, m, n are the direction cosines of a line L then l² + m² + n² = 1. Proof: l = cosα = x/r m = cosβ = y/r n = cos γ = z/r cos²α + cos²β + cos²γ = 1 (x/r) ² + (y/r) Read more about Direction of Cosines and Direction Ratios[…]