化简绝对值sin165° ·cos45°+sin225°·绝对值sin195°的结果是A.0B.-1/2C.1D.1/2

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化简绝对值sin165°·cos45°+sin225°·绝对值sin195°的结果是A.0B.-1/2C.1D.1/2化简绝对值sin165°·cos45°+sin225°·绝对值sin195°的结果

化简绝对值sin165° ·cos45°+sin225°·绝对值sin195°的结果是A.0B.-1/2C.1D.1/2
化简绝对值sin165° ·cos45°+sin225°·绝对值sin195°的结果是
A.0
B.-1/2
C.1
D.1/2

化简绝对值sin165° ·cos45°+sin225°·绝对值sin195°的结果是A.0B.-1/2C.1D.1/2
sin165°cos45°+sin225°|sin195°|
=sin15°cos45°-sin45°*sin15°
=sin(15°-45°)
=-1/2