7, sin5x-sin3x+1-cos4x=2-2sinx
8,2cosx(cos2x-sĩn-cosx)=0
5,sin2x-cos2x=3sinx+cosx-2
6,cos3x+sin7x=2sin^2(pi/4+x/2)-2cos^29x/2
Loga
Sinh Học lớp 12
