Question

sin105°等于多少（带根号）

Answer 1

sin105°=sin( 45°+60°)
=sin45°cos60°+cos45°sin60°
=(√2/2)·1/2+(√2/2)·√3/2
=√2/4+√6/4。

Answer 2

sin105°
=sin(90°+15°)
=sin90°cos15°+cos90°sin15°
=cos15°
=cos(30°/2)
=√((1+cos30°)/2)
=√(2+√3)/2