Not sure if this type of question is allowed, I need to know if my working and my answer is correct. The working is kind of similar to solving a quadratic
$(\tan \theta+1)(\sin^2 \theta -3 \cos^2 \theta)=0$
$(\tan \theta +1)(\sin^2 \theta-3\cos^2 \theta)/(\sin^2 \theta -3\cos^2 \theta )=0/(\sin^2 \theta -3\cos^2 \theta )$
first possible value
second and third possible values
This kind of confused me that there was 3 possible values so I wasn't sure.