Question

what is geometric distribution? please explain or show an example

Answer 1

I'm not sure myself but I found this and it might help
http://www.stat.iastate.edu/homepages/mervyn/Stat330B_Spring2012/Lectures/Set10.pdf

Answer 2

a geometric distribution is a series of yes/no trials (bernoulli trials) needed to get success
for example, the probability that heads comes up on the kth trial is a geometric with variable X for probability P(X=k)

Answer 3

wikipedia is a good source for information like this. There are actually two distributions with this name. See https://en.wikipedia.org/wiki/Geometric_distribution.