21:51:00 04/08/2011
Giải pt 2sin3x(2sin2x+1)=1. Thanks trước.
21:37:00 05/08/2011
Giai pt 16(cos(x+pi/4))^4-4can3cos2x+5=0
10:01:00 06/08/2011
nua nek:1/cos2(x) + 1/2cos2(pi:4-x) -3cot2(x) =3