Ive done this problem several times and I cannot get the ans

I\'ve done this problem several times and I cannot get the answer. please help! For a full rating PLEASE write out every step! The answers to each are in the blue boxes in the pictures, but please explain how you got them with the pi\'s.... ( i couldnt post the 2nd half of b, and all of c).

Solution

f\'(x) = (sin x +1)( 2 cos x + sqrt(3) ) = 0 Sin x = -1 Cos x = -sqrt(3) /2 From these we get (a) f is increasing when f\'(x) > 0 Solving for that we get (b)