should or shouldn't I use "THE" in this situation?
when we are talk about the head such as president, chairman, manager, of a organisation or nation, do we need to use "THE" ? for example
1. President Obama traveled Friday to the Caribbean nation of Trinidad and Tobago for the Fifth Summit of the Americas.
2. He is (the) manager of the team.
3. The most important person in a team is (the) manager.

thank you

Question

should or shouldn't I use "THE" in this situation?
when we are talk about the head such as president, chairman, manager, of a organisation or nation, do we need to use "THE" ? for example
1. President Obama traveled Friday to the Caribbean nation of Trinidad and Tobago for the Fifth Summit of the Americas.
2. He is (the) manager of the team.
3. The most important person in a team is (the) manager.

thank you

Answer

In the first example you're not talking about presidents in general, but president Obama, so no 'the' needed. 
Examples 2 and 3 are correct because you are talking about apt he position of manager, not a specific one. Eg. Assistant manager Dan is the most important member of the team.