1) A_02. Gi¶i ph¬ng tr×nh: 5 cos3x + sin3x sin + 1 2sin2x x    ÷ +   = cos2x + 3 2) D_02. T×m c¸c nghiÖm thuéc [0; 14] cña ph¬ng tr×nh: cos3x - 4cos2x + 3cosx - 4 = 0 3) A_03. Gi¶i ph¬ng tr×nh: cotx - 1 = cos2x 1 + tanx + sin 2 x - 1 2 sin2x 4) D_03. Gi¶i ph¬ng tr×nh: sin 2 ( x 2 - π 4 )tan 2 x - cos 2 x 2 = 0 5) D_04. Gi¶i ph¬ng tr×nh: (2cosx - 1)(sinx + cosx) = sin2x - sinx 6) A_05. Gi¶i ph¬ng tr×nh: cos 2 3xcos2x - cos 2 x = 0 7) D_05. Gi¶i ph¬ng tr×nh: cos 4 x + sin 4 x + cos(x - π 4 )sin(3x - π 4 ) - 3 2 = 0 8) A_05_dù bÞ1. T×m nghiÖm trªn kho¶ng (0 ; π) cña ph¬ng tr×nh: 4sin 2 x 2 - 3 cos2x = 1 + 2cos 2 (x - 3π 4 ) 9) A_05_dù bÞ 2. Gi¶i pt: 2 2 cos 3 ( x - π 4 ) - 3cosx - sinx = 0 10) D_05_dù bÞ 1. Gi¶i pt: tan( 3π 2 - x) + sin 1 cos x x + = 2 11) D_05_dù bÞ 2. Gi¶i pt: sin2x + cos2x - 3sinx - cosx - 2 = 0 12) A_06_dù bÞ 1. Gi¶i pt: cos3xcos 3 x - sin3xsin 3 x = 2 + 3 2 8 13) A_06_dù bÞ 2. Gi¶i pt: 4sin 3 x + 4sin 2 x + 3sin2x + 6cosx = 0 14) B_06_dù bÞ 1. Gi¶i pt: (2sin 2 x - 1)tan 2 2x + 3(2cos 2 x - 1) = 0 15) B_06_dù bÞ 2. Gi¶i pt: cos2x + (1 + 2cosx)(sinx - cosx) = 0 16) D_06_dù bÞ 1. Gi¶i pt: cos 3 x + sin 3 x + 2sin 2 x = 1 17) D_06. Gi¶i pt: cos3x + cos2x - cosx - 1 = 0 18) A_07. Gi¶i ph¬ng tr×nh: (1 + sin 2 x)cosx + (1 + cos 2 x)sinx = 1 + sin2x 19) B_07. Gi¶i ph¬ng tr×nh: 2sin 2 2x + sin7x - 1 = sinx 21) D_07. Gi¶i ph¬ng tr×nh: (sin 2 x 2 + cos 2 x 2 ) 2 + 3 cosx = 2 22) C§_07. Gi¶i ph¬ng tr×nh: 2sin 2 ( π 4 - 2x) + 3 cos4x = 4cos 2 x - 1 23) A_08. Gi¶i ph¬ng tr×nh: 1 1 7π + = 4sin - x 3π sinx 4 sin x - 2    ÷      ÷   24) B_08. Gi¶i ph¬ng tr×nh: sin 3 x - 3 cos 3 x = sinxcos 2 x - 3 sin 2 xcosx 25) D_08. Gi¶i ph¬ng tr×nh: 2sinx(1 + cos2x) + sin2x = 1 + 2cosx 26) C§_08. Gi¶i pt: sin3x - 3 cos3x = 2sin2x A09: GPT (1 2sin ) cos 3 (1 2sin )(1 sinx) x x x − = + − . B09: GPT rf D09: GPT 3 os5 2sin 3 cos 2 s inx 0.c x x x − − = A10: GPT (1 s inx os2 ) sin 1 4 cos . 1 t anx 2 c x x x π   + + +  ÷   = + B10: GPT (sin 2 os2 )cos 2cos 2 sinx 0.x c x x x + + − = D10: GPT sin 2 os2 3sin cos 1 0.x c x x x − + − − = . 2cosx 26) C§_08. Gi¶i pt: sin3x - 3 cos3x = 2sin2x A09: GPT (1 2sin ) cos 3 (1 2sin )(1 sinx) x x x − = + − . B09: GPT rf D09: GPT 3 os5 2sin 3 cos 2 s. 1. Gi¶i pt: cos3xcos 3 x - sin3xsin 3 x = 2 + 3 2 8 13) A_06_dù bÞ 2. Gi¶i pt: 4sin 3 x + 4sin 2 x + 3sin2x + 6cosx = 0 14) B_06_dù bÞ 1. Gi¶i pt: (2sin