Arthur D. answered 02/13/20
Forty Year Educator: Classroom, Summer School, Substitute, Tutor
let x=θ
3tan^3x=tanx
3tan^3x-tanx=0
factor
tanx(3tan^2x-1)=0
tanx=0 and 3tan^2x-1=0
tanx=0 when x=0°, 180°, and 360°
3tan^2x-1=0
3tan^2x=1
tan^2x=1/3
tanx=±√(1/3)
tanx=±√3/3
tan=sin/cos
look on the unit circle
tanx=√3/3 when x=30° and 210°
tanx=-√3/3 when x=150° and 330°
all solutions: x=0°, 30°, 150°, 180°, 210°, 330°, and 360°