sin(50度)*cos(10度)+sin(40度)*sin(10度)=

直接展开就行，下面就不写角度了，直接写数，实际上是角度：
sin50 * cos10 + sin40 * sin10
= 1/2 (sin60 + sin40) - 1/2 (cos50 - cos30)
(这里sin40 = cos50
继续...)
= 1/2 (sin60 + cos30)
= (根号3) / 2

sin(50度)*cos(10度)+sin(40度)*sin(10度)
=sin(50度)*cos(10度)+sin(90度-50度)sin(10度)
=sin(50度)*cos(10度)+cos(50度)sin(10度)
=sin(50度+10度)
=sin60度
=√3/2