ĐÁP ÁN D COS7X.COS5X – 3 SIN2X = 1 – SIN7X.SIN5X ...

câu 100. - 100 CAU HOI TRAC NGHIEM CHUONG i GT 11 LUONG GIAC
100 CAU HOI TRAC NGHIEM CHUONG i GT 11 LUONG GIAC
Câu 100. Đáp án D cos7x.cos5x – 3 sin2x = 1 – sin7x.sin5x

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x312sin75.cos   cos 3k  