1. Giải phương trình:
a, 3(sinx +cosx) - 2sin2x +3 =0
b, 2sin2x + 3 tanx =5
c,$\frac{2}{cosx}= 7sinx -3cosx$
d, $2\sqrt{2}(sinx+cosx)cosx =3+cos 2x$
e, sin4x - cos4x = 1 + $2\sqrt{3}sinxcosx$
f, sin2x +$\sqrt{6}cosx = 3cos^{2}x + \sqrt{2}sinx$
i, cos23x.cos2x - cos2x=0
k, 2cot2x + $2\sqrt{2}sin^{2}x = (2+3\sqrt{2})cosx$