Do you have to capitalize a question that is after a comma? Example:
I'm not hungry, why do I have to eat?
The sentence are formed by dependent clauses with the next structure:
Situation, question about the situation.
They have a luxury car, are they rich?
If I don't study, will I pass the exam?
I'm sure you received my letter, why didn't you answer me?
My question is: the words "are", "will" and "why" have to be capitalized?