If vectors A →= cosωt i^+sinωtj^  and  B→ =  cosωt2i^+sinωt2j^ are functions of time, then the value of t at which they are orthogonal to each other is:

A→ = cosωti^+sinωt j^B→ = cos(ωt2)i^+sinωt2 j^For A→  and  B→  orthogonal  A.→B→ = 0cosωt i^+sinωt j^.cosωt2i^+sinωt2j^ = 0cosωt.cosωt2+sinωt.sinωt2 = 0cos(ωt-ωt2) =0⇒ cosωt2 = 0ωt2 = π2 ⇒ ωt = π  ⇒ t = πω