Question

plzz solve with explanation​

Answer 1

Answer:

$sin(90 + 15) = \cos(15) \\ \\ = > \cos(2x) = 2 {cos}^{2} (x) - 1 \\ \\ = > \cos(30) = 2 {cos}^{2} (15) - 1 \\ \\ = > \cos(15) = \frac{ \sqrt{2 + \sqrt{3} } }{2} \\ \\ so \: \: \sin(105) = \frac{ \sqrt{2 + \sqrt{3} } }{2}$