another trigo equ general solution
These answers can be re-grouped as:
The first group is given in general by and the second group is given by , where n is an integer. These are your answers.
Which is best? It doesn't matter! (But I like yours).
, one of the answers given in the book,
. You can confirm that this is equivalent to , the other answer given in the book.
Method 2 looks like the method the book has used. But I don't know why they decided to use the general solution rather than ....