A.maths

B. By putting x= tan θ and using the result of A. ,solve the equation

x^3 +3√3 x^2 -3x - √3=0 (correct ans to 2 decimal places)
(tan θ )^3+3√3 (tan θ)^2 -3(tan θ) - √3=0
3√3 (tan θ)^2 - √3=3tanθ-tanθ^3
√3 [ (tan θ)^2 -1]=3tanθ-tanθ^3
-√3 [ 1-(tan θ)^2 ]=3tanθ-tanθ^3
tan3θ=-√3
3θ=120,300,480,660,840,1020 (degree)
θ=40,100,160,220,280,340 (degree)
x=tanθ=0.84,-5.67,-0.36,0.84,-5.67,-0.36
θ=