sin(-1071°)sin99°+sin(-171°)sin(-261°)
=sin(-1071°+3×360°)sin(90°+9°)+sin(-180°+9°)sin(-360°+99°)
=sin9°cos9°-sin(180°-9°)sin(90°+9°)
=1-sin9°cos9°
=1-1
=0
高一数学化简sin(-1071°)*sin99°+sin(-171°)*sin(-261°)
高一数学化简sin(-1071°)*sin99°+sin(-171°)*sin(-261°)
数学人气:856 ℃时间:2020-02-05 07:22:55
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