PHƯƠNG TRÌNH LƯỢNG GIÁC.
1/ cos23x.cos2x – cos2x = 0 2/ 1 + sinx + cosx + sin2x + cos2x = 0
3/ cos4x + sin4x + cos .
4
−x π sin
4
3x π -
2
3
= 0 4/ 5sinx – 2 = 3(1 – sinx)tan2x
5/ (2cosx – 1)(2sinx + cosx) = sin2x – sinx 6/ cotx – 1 = sin 21
tan 1
2
− +
x
sin2x
2 cos tan
4 2
x
x π
2 sin 2 1
3 sin 3 cos
sin
+
+
x
x x
x với 0 < x < 2π 10/ sin23x – cos24x = sin25x – cos26x 11/ cos3x – 4cos2x + 3cosx – 4 = 0 với 0 ≤x≤ 14
12/ cosx + cos2x + cos3x = sinx + sin2x + sin3x 13/ 3 sin 2x− 2 2 sin 2x= 6 − 2
14/ cos3x + sin7x = 2 2 cos 92
2
5 4
−
+ π
15/ sin3x + sinx.cosx = 1 – cos3x 16/ 2 + cos2x = 2tanx 17/ sinx.cosx + cos2x =
2
1
2 +
−
=
2 4 sin 3 4 2
3
19/ sin3x + cos2x =2 ( sin2x.cosx – 1) 20/ 4cosx – 2cos2x – cos2x – cos4x = 0 21/ 1
2 cos 1
2
+
+
x x
22/ cosx + sin2x = 0 23/ 2(cos4x – sin4x) + cos4x – cos2x = 0 24/ (5sinx – 2)cos2x = 3(1 – sinx)sin2x 25/ (2sinx – 1)(2cosx + sinx) = sin2x – cosx
+
=
+ +
+
4
cos 6
cos 3
28/ sin3x + cos3x = sinx – cosx 29/ x 2 sin x tanx
4 sin
.
− π
30/ 4cos2x – 2cos22x = 1 + cos4x 31/ cos3x.sìnx – cos4x.sinx = sin 3x 1 cosx
2
1
+
32/ (2sinx – 1)(2cos2x + 2sinx + 3) = 4sin2x – 1 33/ cosx.cos7x = cos3x.cos5x
2 cos
cos
2 sin
−
−
x x
x x
35/ sinx + sin2x + sin3x = 0
x x
x
8
13 sin
cos
sin
cos
2 2
6 6
=
−
+ 37/ cos2x.sin4x + cos 2x = 2cosx(sinx + cosx) – 1 38/ 3 – tanx(tanx + 2sinx) + 6cosx = 0 39/ cos2x + cosx(2tan2x – 1) = 2
40/ 3cos4x – 8cos6x + 2cos2x + 3 = 0 41/
1 cos 2
4 2 sin 2 cos ) 3 2
−
−
−
−
x
x
= 1
cos sin
) 1 (cos
cos 2
x x
x
x
+
− 43/ cotx = tanx + 2sincos24x x
44/
x
x x
x x
2 sin 8
1 2
cot 2
1 2
sin
.
5
cos
sin 4 4
−
=
x
x x
2 4
cos
3 sin ) 2 sin 2 ( 1
46/ tanx + cosx – cos2x = sinx(1 + tanx.tan )
2
x
47/ sin(π cosx) = 1
48/ cos3x – sìnx = 3(cos2x - sin3x) 49/ 2cos2x - sin2x + sinx – cosx = 0 50/ sin3x + cos2x = 1 + sinx.cos2x 51/ 1 + sinx + cosx + sin2x + cos2x = 0
Trang 252/ cos2x + 5sinx + 2 = 0 53/ cos2x.sin2x + cos2x = 2(sinx + cosx)cosx – 1 54/ 8.sin2x + cosx = 3.sinx + cosx 55/ 3cos2x + 4cos3x – cos3x = 0
56/ 1 + cosx – cos2x = sinx + sin2x 57/ sin4x.sin2x + sin9x.sin3x = cos2x
58/ 1 + sinx+ cosx= 0 59/ 3 cosx(1 − sinx)− cos 2x= 2 sinx sin 2 x− 1
2
cos
2
sin
2
= +
=
−
x
7 sin 4 2
3 sin
1 sin
π
62/ 2sin22x + sin7x – 1 = sinx 63/ 0
sin 2 2
cos sin ) sin (cos
=
−
− +
x
x x x
x
2 tan tan
x 65/ cos3x + cos2x – cosx – 1 = 0