sin(x-27°)cos(18°-x)-sin(【63°】-x)sin(x-18°)
=sin(x+27°)cos(18°-x)+cos(90°-【63°-x】)sin(18°-x)
=sin(x+27°)cos(18°-x)+cos(90°-63°+x)sin(18°-x)
=sin(x+27°)cos(18°-x)+cos(27°+x)sin(18°-x)
=sin45°
=√2/2
sin(x-27°)cos(18°-x)-sin(60°-x)sin(x-18°)
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