P is a point on the segment joining the feet of two vertical poles of heights a and b. The angles of elevation of the tops of the poles from P are 45° each. Then, the square of the distance between the tops of the poles is
A.
If cos(x - y), cos(x), cos(x + y) are three distinct numbers which are in harmoric progression and cos(x) cos(y), then 1 + cos(y) is equal to
The sum of angles of elevation of the top of a tower from two points distant a and b from the base and in the same straight line with it is 90°. Then, the height of the tower is
ab2
ab