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

-
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

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

(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
+ + − =