PHƯƠNG TRÌNH LƯỢNG GIÁC. 1/ cos 2 3x.cos2x – cos 2 x = 0 2/ 1 + sinx + cosx + sin2x + cos2x = 0 3/ cos 4 x + sin 4 x + cos . 4 − π x sin − 4 3 π x - 2 3 = 0 4/ 5sinx – 2 = 3(1 – sinx)tan 2 x 5/ (2cosx – 1)(2sinx + cosx) = sin2x – sinx. 6/ cotx – 1 = 2 1 sin tan1 2cos 2 −+ + x x x sin2x. 7/ cotx – tanx + 4sin2x = x2sin 2 8/ 0 2 costan. 42 sin 222 =− − x x x π 9/ 32cos 2sin21 3sin3cos sin5 += + + + x x xx x với 0 < x < 2 π 10/ sin 2 3x – cos 2 4x = sin 2 5x – cos 2 6x 11/ cos3x – 4cos2x + 3cosx – 4 = 0 với 0 ≤≤ x 14 12/ cosx + cos2x + cos3x = sinx + sin2x + sin3x 13/ 26sin.222sin.3 2 −=− xx . 14/ cos3x + sin7x = 2. 2 9 cos2 2 5 4 sin 22 xx − + π 15/ sin 3 x + sinx.cosx = 1 – cos 3 x 16/ 2 + cos2x = 2tanx 17/ sinx.cosx + cos 2 x = 2 12 + 18/ −= + 24 sin.3 42 3 sin xx ππ 19/ sin3x + cos2x =2 ( sin2x.cosx – 1) 20/ 4cosx – 2cos 2 x – cos2x – cos4x = 0 21/ 1 2cos1 2sin = + + x x 22/ cosx + sin2x = 0 23/ 2(cos 4 x – sin 4 x) + cos4x – cos2x = 0 24/ (5sinx – 2)cos 2 x = 3(1 – sinx)sin 2 x 25/ (2sinx – 1)(2cosx + sinx) = sin2x – cosx 26/ cos3x + 2cos2x = 1 – 2sinxsin2x 27/ += ++ + 4 cos 6 cos 3 cos πππ xxx 28/ sin 3 x + cos 3 x = sinx – cosx 29/ xxx tansin.2 4 sin.2 22 −= − π 30/ 4cos 2 x – 2cos 2 2x = 1 + cos4x 31/ cos3x.sìnx – cos4x.sinx = xx cos13sin 2 1 ++ . 32/ (2sinx – 1)(2cos2x + 2sinx + 3) = 4sin 2 x – 1 33/ cosx.cos7x = cos3x.cos5x 34/ 3 2coscos 2sinsin = − − xx xx 35/ sinx + sin2x + sin3x = 0 36/ x xx xx 2tan 8 13 sincos sincos 22 66 = − + 37/ cos 2 x.sin 4 x + cos 2x = 2cosx(sinx + cosx) – 1 38/ 3 – tanx(tanx + 2sinx) + 6cosx = 0 39/ cos2x + cosx(2tan 2 x – 1) = 2 40/ 3cos4x – 8cos 6 x + 2cos 2 x + 3 = 0 41/ 1cos2 42 sin2cos)32( 2 − −−− x x x π = 1 42/ )sin1(2 cossin )1(coscos 2 x xx xx += + − 43/ cotx = tanx + x x 2sin 4cos2 44/ x x x xx 2sin.8 1 2cot 2 1 2sin.5 cossin 44 −= + 45/ x xx x 4 2 4 cos 3sin)2sin2( 1tan − =+ 46/ tanx + cosx – cos 2 x = sinx(1 + tanx.tan ) 2 x 47/ sin( 1)cos. = x π 48/ cos3x – sìnx = 3 (cos2x - sin3x) 49/ 2cos 2 x - sin2x + sinx – cosx = 0 50/ sin3x + cos2x = 1 + sinx.cos2x 51/ 1 + sinx + cosx + sin2x + cos2x = 0 52/ cos2x + 5sinx + 2 = 0 53/ cos 2 x.sin 2 x + cos2x = 2(sinx + cosx)cosx – 1 54/ 8.sin 2 x + cosx = 3 .sinx + cosx 55/ 3cos2x + 4cos 3 x – cos3x = 0 56/ 1 + cosx – cos2x = sinx + sin2x 57/ sin4x.sin2x + sin9x.sin3x = cos 2 x 58/ 0cossin1 =++ xx 59/ ( ) 1sin.sin22cossin1cos3 2 −=−− xxxxx 60/ 2cos.3 2 cos 2 sin 2 =+ + x xx 61/ −= − + x x x 4 7 sin4 2 3 sin 1 sin 1 π π 62/ 2sin 2 2x + sin7x – 1 = sinx 63/ 0 sin22 cossin)sin(cos2 66 = − −+ x xxxx 64/ cotx + sinx 4 2 tan.tan1 = + x x 65/ cos3x + cos2x – cosx – 1 = 0