From an inclined plane two particles are projected with same speed at same angle θ, one up and the other down the plane as shown in fig. (3). Which statement(s) is/are correct?

The projection of projectiles P and Q are separately shown in fig, (a and b) respectively.The time of flight of P is given byTp=2usin⁡(α−β)gcos⁡β=2usin⁡(2θ−θ)gcos⁡θ=2utan⁡θgThe time of flight of Q is given byTQ=2usin⁡(α+β)gcos⁡β=2usin⁡θgcos⁡θ=2utan⁡θg∴ TP=TQ