Articles in essays
Hello, I was wondering: When you put an article "a"/"an" in a title of essay, will you write "the" in essay if you will use a noun from the title?
Example:
Title of the essay: A Dog And Me
Beginning of the essay: The dog was cheerful that day, I felt energy flowing from him...
I used an "a" article in the title and began the essay with "the" in this case. Is it right?
Thank you for all answers!

Question

Articles in essays
Hello, I was wondering: When you put an article "a"/"an" in a title of essay, will you write "the" in essay if you will use a noun from the title? 
Example:
Title of the essay: A Dog And Me
Beginning of the essay: The dog was cheerful that day, I felt energy flowing from him...
I used an "a" article in the title and began the essay with "the" in this case. Is it right?
Thank you for all answers!

Answer

You could use "the" or "a" in the title.  The title need have no relation to the first line or the introduction.  The title is not part of the text.  So you could write for example: "A dog called Rover" or "The dog next door".

Answer

Since the title is not part of the text, you would need to introduce the dog properly in the text.

"The dog was cheerful that day..." No, I don't know which dog you mean. You'll need to tell us.