settlement set of this trigonometric equations

Question

cos (x+75°) = 1/2 ,0°≤ x ≤ 360°

Answer 1

In degrees, the function cos(a) is 1/2 at

a = 60^o

a = -60^o

a = 300^o

a = -300^o So x + 75 = a implies that

x = 60-75 = -15^o

x = -60-75 = -135^o

x = 300-75 = 225^o

x = -300-75 = -375^{o If your constraint does not include the negative values, disregard them!}