Trigo. Equations

a.
(tanθ - 1)(sinθ - 1)(cosθ - 1) = 0
tanθ - 1 = 0 or sinθ - 1 = 0 or cosθ - 1 = 0
tanθ = 1 or sinθ = 1 or cosθ = 1
θ = 45° , 225° or θ = 90° (rejected since tan90° is undefine) or θ = 0°
So θ = 0° , 45° , 225° for 0° =< θ < 360°
b.
(cosθ)(sinθ + 1) = 0
cosθ = 0 or sinθ + 1 = 0 i.e. sinθ = - 1
θ = 90° or θ = 270° for 0° =< θ < 360°