http://i952.photobucket.com/albums/a...g/P5250091.jpg

The diagram shows an isosceles triangle with fixed length and of each and Angle Angle radians.

is a variable point which is at a height directly above the point while and are variable points which move horizontally along the line .

Given that descends vertically towards the point such that the area of triangle is decreasing at a constant rate of , determine, at the instant when is above , the rate of change of

but the answer is -0.025

And another part of the question asks : Find the rate at which C is moving away from O. I could not start