Answer :
I would subtract 1sin(Θ) from each side of the equation.
The equation would then say that 2sin(Θ) = -1 .
I would only have to find angles whose sin is -1/2 ,
and those would be my solutions.
3sinΘ = sinΘ - 1
3sinΘ - sinΘ = sinΘ - sinΘ - 1
2sinΘ = -1
2sin 2sin
Θ = -2.864934497
3sinΘ - sinΘ = sinΘ - sinΘ - 1
2sinΘ = -1
2sin 2sin
Θ = -2.864934497