A common way to characterize the frequency content of a random process is in terms of the number of "zero-crossings" in a given interval of time. One can define "zero-crossing" for a discrete-time signal or sequence as whenever the sequence changes from a positive to a negative value or vice-versa. Consider a Bernoulli sequence over some time interval 0,-1. What are the probabilities for 0 zero-crossings and 1 zero crossing in this interval? Write also a recursive formula that expresses the probability of zero-crossings in termsof the probability of -1 zero-crossings in some interval of length .