Answer
$\emptyset$
Work Step by Step
Substitute t=$\sin\theta$
$ t^{2}-2t+3=0\qquad$...quadratic formula...
$t=\displaystyle \frac{2\pm\sqrt{4-12}}{2}$
has no real solutions,
as the discriminant $b^{2}-4ac$ is negative
So, the solution set is an empty set.