A circular cylinder of height 6 cm and base radius 4cm sits on a table with its axis vertical. A point source of light moves vertically upwards at a speed of 3cm/s above the central axis of the cylinder, thus casting a circular shadow on that table. Find the rate at which the radius of the...
A straight railway track and a straight road intersect at right angles. AT a given instant, a motor car at 40 km/h and a train at 50km/h are moving away from the intersection and are 40km and 30 km respectively away from the intersection. At what rate is the distance between them changing one...
The base of a solid is the region by the graphs of f(x)=x^2 and g(x) = 8 - x^2. Find the volume of solid if all the cross sections perpendicular to the x- axis are squares.