V

Cos[θ + π/2] = -Sin[θ]

Sin[θ + π/2] = Cos[θ]

Cos[θ + π] = -Cos[θ]

Sin[θ + π] = -Sin[θ]

Vx == -Dv Sin[θ], Vy == Dv Cos[θ]

V1x == Dv1 Cos[θ], V1y == Dv1 Sin[θ]

V2x == -Dv2 Cos[θ], V2y == -Dv2 Sin[θ]

V1y = (Vy - By)/(Vx - Bx) (V1x - Bx) + By

V2y = (Vy - By)/(Vx + Bx) (V2x + Bx) + By

Solve