## Precalculus (6th Edition)

$\emptyset$
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.