问题
填空题
计算
|
答案
+1 sin50° 3 cos50°
=cos50°+
sin50°3 sin50°cos50°
=2(
cos50°+ 1 2
sin50°)3 2 sin50°cos50°
=2(sin30°cos50°+ cos30°sin50°) sin50°cos50°
=
=2sin(30°+50°) sin50°cos50° 2sin80° sin50°cos50°
=2sin80°
sin100°1 2
=2sin80°
sin80°1 2
=4
故答案为4