CHUYÊN ĐỀ: PHƯƠNG TRÌNH LƯỢNG GIÁC.
GIẢI CÁC PHƯƠNG TRÌNH SAU:
1/ 3sin22x + 7cos2x -3=0
2/ 6cos2x + 5sinx -7=0
3/ cos2x - 5sinx-3 = 0
4/ cos2x + cosx + 1= 0
5/ 7tanx - 4cotx = 12
6/ 4tan4x + 12tan2x = 7
7/ 4sinx - 3cosx = 5
8/ 2cos2x + 3sin2x = 3
9/ sin2x - 2sinxcosx - 3cos2x = 0
10/ sin2x - 2sin2x = 2cos2x
11/ 6sin2x + sinxcosx -cos2x = 2
12/ 2sin3x + 4cos3x = 3sinx
13/ sinxsin7x = sin3xsin5x
14/ cosxcos3x - sin2xsin6x - sin4xsin6x = 0
15/ cosx + cos3x + 2cos5x = 0
16/ co22x + 3cos18x + 3co14x + co10x = 0
sin x + sin 2 x + sin 3 x = 3/ 2
cos x + cos 2 x + cos 3 x + cos 4 x = 2
19/ sin4x+ cos4x = cos4x
20/ sin2xtan2x + cos2xcotx-sin2x = 1+tanx + cotx
21/(2sinx - 1)(2sin2x + 1)= 3 - 4cos2x
22/ 3sin 3 x − 3 cos9 x = + 1 sin3x
23/2 2(sin x + cos ) cos x x = + 3 cos 2 x
x − π + x + π + x + π =
25/4sin3x cos3 x + 4cos3x sin 3 x + 3 3 cos 4 x = 3
cos
x x
x
27/ 2(sin x + cos ) sin cos x − x x = 1
29/sin23x - cos24x = sin25x - cos26x
30/ Tìm nghiệm thuộc khoảng(0; 2 ) π của PT:
cos3x+sin3x
31/ Tìm x thuộc đoạn [0;14]nghiệm đúng PT:
cos3x - 4cos2x + 3cosx - 4 = 0
32/
cot 2
x x
x
33/
2 4
4
(2 sin 2 )sin 3
cos
x x x
x
− + =
34/ tanx+cosx-cos2x= sinx(1+tanxtanx/2)
35/ 2sin cos 1 1
x x
36/ 12
sin
x
x
+ 38/ 3- tanx(tanx+2sinx)+6cosx=0 39/ cos2x+cosx(2tan2x-1) = 2 40/ cotx-tanx+4sin2x=2/sin2x 41/ 3cos4x - 8cos6x + 2cos2x + 3 = 0
42/
2
x x
x
π
=
−
x
π
44/
2
2(1 sin )
x x
x
x − = + x
+
sin 2
x
x x
x
3 (1 2sin )(1 sin )
x x
47/ sin x + cos sin 2 x x + 3 cos3 x = 2(cos 4 x + sin )3x
48/ 3 cos5 x − 2sin 3 cos 2 x x − sin x = 0
49/ (1 2sin ) cos + x 2 x = + 1 sin x + cos x
π π
−