Which data structures can erase from its beginning or its end in O(1) time

A fair coin is tossed eight xx,then find the probability that resulting sequence of heads and tails looks the same when viewed from the beginning or from the end.

Rs 200000is the cost of Revenue from operations(Cost of goods sold) during the year if iventory turnover ratio is 8 times calculate inventories at the end tof the year inventories at the end is 1.5 times that of in the beginning.

A particle is performing damped oscillation with frequency 5Hz . After every 10 oscillations its amplitude becmoes half. Find time from beginning after which the amplitude becomes 1//1000 of its initial amplitude :

A rod of unifrom cross section is heated at temperature t_(0) at a point which is at n_(1) times if its length (n_(1) lt 1) from its one end in stready state The temperature at this end is t_(1) and at other end is t_(2) Rate of vapourisation of water at either end of the rod is same. The end at which temperature is t_(2) is how much more far away that the other end from the point at which the rod is heated .

Find the locus of a point which moves such that its distance from the origin is three xx its distance from x-axis.

A string of linear mass density 0.5 g cm^-1 and a total length 30 cm is tied to a fixed wall at one end and to a frictionless ring at the other end. The ring can move on a vertical rod. A wave pulse is produced on the string which moves towards the ring at a speed of 20 cm s^-1 . The pulse is symmetric about its maximum which is located at a distance of 20 cm from the end joined to the ring. (a) Assuming that the wave is reflected from the ends without loss of energy, find the time taken by the string to regain its shape. (b) The shape of the string changes periodically with time. Find this time period. (c) What is the tension in the string ?