question_answer

As observed from the top of a light house, 100 m high above sea level, the angles of depression of a ship, sailing directly towards it, changes from to. Find the distance travelled by the ship during the period of observation. (Use)

Answer:

Let CD be a light house of length 100 m and A and B be the positions of ship sailing towards it.

Then, in ,

And, in

Distance travelled by the ship