If A and B are square matrices of order 3 such that |A| = –1, |B| = 3, then find the value of |2AB|.
A balloon, which always remains spherical, has a variable diameter . Find the rate of change of its volume with respect to x.
How many equivalence relations on the set {1, 2, 3} containing (1, 2) and (2, 1) are there in all ?Justify your answer.
The radius r of a right circular cylinder is decreasing at the rate of 3 cm/min. and its height h is increasing at the rate of 2 cm/min. When r =7 cm and h = 2 cm, find the rate of change of the volume of cylinder.