(人教a版·数学理)浙江专用答 【解析】(1)cos15°=cos(45°
log2sin15° log2sin30° log2sin 45°=
cos105=cos(45 60) =cos45cos60-sin45sin60 =√2/2x1/2-√2/2x√3/2
(人教a版·数学理)浙江专用答 【解析】(1)cos15°=cos(45°
log2sin15° log2sin30° log2sin 45°=
cos105=cos(45 60) =cos45cos60-sin45sin60 =√2/2x1/2-√2/2x√3/2