Q1.The angles of elevation of the top of a building from the top and bottom of a tree are x and y respectively. If the height of the tree is h metre, then, in metre, the height of the building is
(a) (h cotx)/(cotx+coty )
(b) (h coty)/(cotx+coty )
(c) (h cotx)/(cotx-coty )
(d) cotx/(cotx+coty )