A stick of proper length L p makes an angle with the x axis in frame S. Show that the angle made with

A stick of proper length L_p makes an angle θ with the x axis in frame S. Show that the angle θ‘ made with the x’ axis in frame S’, which is moving along the +x axis with speed V, is given by tan θ‘ = γ tan θ and that the length of the stick in S’ is

1/2 L' = L -cos2 0+ sin2 0