[r]
(1)MỘT SỐ BÀI TẬP LƯỢNG GIÁC 11 Bài 1: Giải phương trình:
1/ cos6x −sin6x=13 cos
2
2x 2/ sin8x+cos8x=17 16 cos
2 2x
3/ sin 3x=3sin 5x 4/
3(sin8x+cos8x)−6(sin10x+cos10x)=7 cos 2x 5/ 1+2 cos2 4x
5 6/ cos
x=cos4x
3 7/ sin
2x+cos8x=1 8/ sin8x
+cos8x=2(sin10x+cos10x)+5
4cos 2x 9/
sinxcot 5x
cos 9x =1
10/ sin
x+cos4x sin 2x =
1
2(tanx+cotx) 11/
sinx+sin2x+sin 3x cosx+cos 2x+cos 3x=√3 12/ 3(cot 2x+cos 2x)
cot 2x −cos 2x −2 sin 2x=2 13/
1
tanx+cot 2x =
√2(cosx −sinx) cotx −1
14/ sin2x −sinx+ sin2x−
1
sinx=0
15/cos2x+cos4x+cos6x=cosxcos2xcos3x+2 16/4cosx-2cos2x-cos4x =1
17/sin4x-cos4x =1+4(sinx-cosx) 21/ (sinx+√3 cosx)sin 3x=2 18/ cos5x+sin5x+sin 2x+cos 2x=1+√2 22/cotx = tanx+2tan2x 19/
sinx+√2−sin2x+sinx√2−sin2x=3 23/3(tanx+cotx)=2(2+sin2x) 20/
4(sin 10x
+cos10x)=sin 6x
+cos6x
sin22x+4 cos22x 24/ cos
x+sin3x+cosx=0 25/ cos24x+cos28x=sin212x+sin216x+2 26/3(cotx-cosx)-5(tanx-sinx)=2 27/ tan3x −cot3x −3
(tan2x+cot2x)−12(tanx −cotx)+8=0 28/ tan3x −cot3x −3
(tan2x+cot2x)−3(tanx −cotx)+10=0 29/ 4(tan2x+cot2x)−4(tanx −cotx)−7=0 30/