Bài tập về phương trình lượng giác ôn thi đại học môn toán

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 ................................................................................. 17/ 2 2 2 sin sin 2 sin 3 3/ 2 x x x + + = 18/ 2 2 2 2 cos cos 2 cos 3 cos 4 2 x x x x + + + = 19/ sin4x+ cos4x = cos4x 20/ sin2xtan2x + cos2xcotx-sin2x = 1+tanx + cotx 21/(2sinx - 1)(2sin2x + 1)= 3 - 4cos2x

22/ 3 3sin 3 3 cos9 1 sin x x x − = +

23/2 2(sin cos )cos 3 cos2 x x x x + = +

24/ 3sin( ) 4sin( ) 5sin(5 ) 0 3 6 6 x x x π π π − + + + + =

25/ 3 3 4sin cos3 4cos sin3 3 3 cos4 3 x x x x x + + =

26/ 1 3sin cos cos x x x + =

..................................................................................

27/ 2(sin cos ) sin cos 1 x x x x + − =

28/ 1 1 1 cos sin cos sin 3 x x x x + + + =

29/sin23x - cos24x = sin25x - cos26x 30/ Tìm nghiệm thuộc khoảng(0;2 ) π của PT: cos3x+sin3x 5(sinx+ ) cos2 3 1+2sin2x x = +

31/ Tìm x thuộc đoạn [0;14]nghiệm đúng PT: cos3x - 4cos2x + 3cosx - 4 = 0

32/

4 4 sin cos 1 1 cot 2 5sin 2 2 8sin 2 x x x x x + = −

33/

2 4 4 (2 sin 2 )sin3 tan 1 cos

x x x x − + =

34/ tanx+cosx-cos2x= sinx(1+tanxtanx/2)

35/ 2sin cos 1 1 sin 2cos 3 3 x x x x + + = − +

36/ 2 1 sin 8cos x x =

37/ 2 cos2 1 cot 1 sin sin 2 1 tan 2 x x x 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 (2 3)cos 2sin ( ) 2 4 1 2cos 1

x x

x

π − − −

= −

43/ 2 2 2 sin ( )tan cos 0 2 4 2 x x x π − − =

44/

2 cos (cos 1) 2(1 sin ) sin cos x x x x x − = + +

45/ 2cos4 cot tan sin 2

x x x x = +

46/ (1 2sin )cos 3 (1 2sin )(1 sin ) x x x x − = + −

47/ 3 sin cos sin 2 3 cos3 2(cos4 sin ) x x x x x x + + = +

48/ 3 cos5 2sin3 cos2 sin 0 x x x x − − =

49/ 2 (1 2sin ) cos 1 sin cos x x x x + = + +

50/ 1 1 7 4sin( ) sin sin( 3 / 2) 4 x x x

π π + = − −