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hatcat_sad


giải phương trình:
1) ( cos^2 x+ 1/cos^2 x)^2 + ( sin^2 x +1/sin^2 x)^2 = 12 +1/2.sinx
2) 7cos^2 x + cos^2008 x =1
3) sin^3(x-pi/4) =căn2.sinx
1) ( cos^2 x+ 1/cos^2 x)^2 + ( sin^2 x +1/sin^2 x)^2 = 12 +1/2.sinx
2) 7cos^2 x + cos^2008 x =1
3) sin^3(x-pi/4) =căn2.sinx