题目内容
sin7°cos37°﹣sin83°cos53°的值为( )
A.﹣
B.
C.
D.﹣![]()
A
【解析】sin7°cos37°﹣sin83°cos53°
=cos83°cos37°﹣sin83°sin37°
=cos(83°+37°)
=cos120°
=﹣
,
故选A.
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题目内容
sin7°cos37°﹣sin83°cos53°的值为( )
A.﹣
B.
C.
D.﹣![]()
A
【解析】sin7°cos37°﹣sin83°cos53°
=cos83°cos37°﹣sin83°sin37°
=cos(83°+37°)
=cos120°
=﹣
,
故选A.