(a) Express 3cosx + 2sinx in the form Rcos(x – α), where R and α are constants with R 1 0 and
0° < α < 90°. 
(b) Find all values of x between 0° and 360° satisfying
3cosx + 2sinx = 1. 
For (a), I have
and in (b), I got up to saying , but I have no idea what is done after this to get the values of x.
How is this done? Thanks if you're able to help me