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计算
1
sin50°
+
3
cos50°
=______．
人气：393 ℃　时间：2020-05-25 12:39:22
解答
1
sin50°
+
3
cos50°

=
cos50°+
3
sin50°
sin50°cos50°

=
2(
1
2
cos50°+ 
3
2
sin50°)
sin50°cos50°

=
2(sin30°cos50°+  cos30°sin50°)
sin50°cos50°

=
2sin(30°+50°)
sin50°cos50°
=
2sin80°
sin50°cos50°

=
2sin80°
1
2
sin100°

=
2sin80°
1
2
sin80°

=4
故答案为4
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