Please explain in detail using words and problems.

11. Explain that (a) tan 0 - sin 0 cos ! ' (b) sin2 0 + cos2 0 = 1. (Here sin2 0 means (sin 0)2. Similarly for cosine.) Using this, answer the following questions: If we know cos 0 = 1, 3, what is sin 0, if . 0