how can i find a general solution of g(x)when they give me g(X) =cos (x+30)and g(X)= -2sinx

Answer 1

well, when does

cos(x+30) = -2sinx
√3/2 cosx - 1/2 sinx = -2sinx
√3/2 cosx = -3/2 sinx
tanx = -1/√3
since tan30 = 1/√3,
x = (180-30) or (360-30) = 150 or 330
or, more generally,

x = 180n-30 for any integer n