Let L be the set of all lines in XY plane and R be the relation in L defined as R = {(L1, L2): L1 is parallel to L2 }. Show that R is an equivalence relation. Find the set of all lines related to the line y = 2x + 4.
Prove: \(cos^{-1} \frac {12}{13} + sin^{-1} \frac 35 = sin^{-1} \frac {56}{65}\)
Write two different vectors having the same direction.