题目内容
sin7°cos37°-sin83°cos53°的值为( )
A.-
| B.
| C.
| D.-
|
sin7°cos37°-sin83°cos53°
=cos83°cos37°-sin83°sin37°
=cos(83°+37°)
=cos120°
=-
,
故选A.
=cos83°cos37°-sin83°sin37°
=cos(83°+37°)
=cos120°
=-
| 1 |
| 2 |
故选A.
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