Solve in R :
@OP: Expanding a little on this hint:
You can therefore write .
Now solve for using the fact that if sin A = sin B then:
Case 1:
Case 2:
where n is an integer.
Now that you know the values of x for which you should be able to write down the intervals over which .
(drawing a graph might help ....)
Yes, we understood that! Apparently you did not understand the solution. Since the functions here are continuous, they can only change from "<" to ">" and vice-versa at "=". First solve the equation, then, as mr. fantastic said, check the intervals between the solutions to the equation to see where it is ">" and "<".