The questions that you have posed here look to be either test questions or questions for homework.
We don't help people cheat on tests here. Pull out your notes and your book and review the material so you are better able to finish this on your own.
5. What are the frequencies and relative amplitudes of the first four component waves to a 200 Hz square wave? (Assume the fundamental has amplitude 1).
What kind of waves are you talking about? Cosine waves? Ocean waves? And what frequency are these first 4 components you are talking about? More information is needed to answer the question as stated.