Hi, Please give me answer regarding Long tail keywords and short keyword so my question is which is the best Log tail of short keyword...
Both are good. But use them wisely. Use the short keyword on the Meta Tags & the Long Tail keyword on the Articles & blogs.
long tailed key words are, in fact, holds the higher probability of unique key words and it holds probability function of all unite keywords that made the keyword long. For example, for the keywords "Learning computer networking course online" has "Learn computer", "Learn computer networking", "computer networking", "computer networking course", "networking course", "networking course online" keywords inside. So, what ever be the searching keywords of search engine users, you got the probability for all Keywords and taggs. Now with making good backlinks you will get PR quickly; but your domain name must be closer to your keywords as well and it must be unique too.
Long tailed keywords will have much less competition therefore it will be easy for you to rank for them quickly. Short tailed keywords have much larger competition therefore you would have to do more work in order to rank for them.