You can immediately reject the first one, because $\displaystyle \frac{1+\sqrt{3}}{2}$ is greater than 1.

If you're wondering whether solving $\displaystyle \sin(x) = \frac{1-\sqrt{3}}{2}$ is supposed to give you a "nice" angle, the answer is no. I get x = -21.47 degrees (approx). I used the calculator to get that answer.