R
rapworld


Giải pt:
1) 3 - 4cos^2 2x - 2cos2x(2sinx -1)
2) sin5x - cos2x - sin3x +1=0
3) sin^3 2x.cos6x + sin6x.cos^3 2x= 3/8
C/m:
(1 - sin2x) / (1+ sin2x) = tan^2 (bi/4 - x)
1) 3 - 4cos^2 2x - 2cos2x(2sinx -1)
2) sin5x - cos2x - sin3x +1=0
3) sin^3 2x.cos6x + sin6x.cos^3 2x= 3/8
C/m:
(1 - sin2x) / (1+ sin2x) = tan^2 (bi/4 - x)
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