CHUYÊN ĐỀ: PHƯƠNG GIẢI CÁC PHƯƠNG TRÌNH SAU: 1/ 3sin22x + 7cos2x -3=0 2/ 6cos2x + 5sinx -7=0 3/ cos2x - 5sinx-3 = 4/ cos2x + cosx + 1= 5/ 7tanx - 4cotx = 12 6/ 4tan4x + 12tan2x = 7/ 4sinx - 3cosx = 8/ 2cos2x + 3sin2x = 9/ sin2x - 2sinxcosx - 3cos2x = 10/ sin2x - 2sin2x = 2cos2x 11/ 6sin2x + sinxcosx -cos2x = 12/ 2sin3x + 4cos3x = 3sinx 13/ sinxsin7x = sin3xsin5x 14/ cosxcos3x - sin2xsin6x - sin4xsin6x = 15/ cosx + cos3x + 2cos5x = 16/ co22x + 3cos18x + 3co14x + co10x = 17/ sin x + sin 2 x + sin x = / 18/ cos x + cos 2 x + cos x + cos x = 19/ sin4x+ cos4x = cos4x 20/ sin2xtan2x + cos2xcotx-sin2x = 1+tanx + cotx 21/(2sinx - 1)(2sin2x + 1)= - 4cos2x 22/ 3sin x − cos x = + sin x 23/ 2(sin x + cos x ) cos x = + cos x 24/ 3sin( x − π π π ) + 4sin( x + ) + 5sin(5 x + ) = 6 3 25/ sin x cos x + cos x sin x + 3 cos x = 26/ sin x + cos x = cos x 27/ 2(sin x + cos x) − sin x cos x = 28/ cos x + 1 + sin x + = cos x sin x 29/sin23x - cos24x = sin25x - cos26x 30/ Tìm nghiệm thuộc khoảng (0; 2π ) PT: 5(s inx+ cos3x+sin3x ) = cos x + 1+2sin2x 31/ Tìm x thuộc đoạn [0;14]nghiệm PT: cos3x - 4cos2x + 3cosx - = sin x + cos x 1 = cot x − 5sin x 8sin x (2 − sin x)sin x 33/ tan x + = cos x 32/ 34/ tanx+cosx-cos2x= sinx(1+tanxtanx/2) 35/ sin x + cos x + 1 = sin x − cos x + 3 TRÌNH LƯỢNG GIÁC = sin x 8cos x cos x 37/ cot x − = + sin x − sin x + tan x 36/ 38/ 3- tanx(tanx+2sinx)+6cosx=0 39/ cos2x+cosx(2tan2x-1) = 40/ cotx-tanx+4sin2x=2/sin2x 41/ 3cos4x - 8cos6x + 2cos2x + = 42/ 43/ 44/ 45/ 46/ x π (2 − 3) cos x − sin ( − ) =1 cos x − x π x sin ( − ) tan x − cos = 2 cos x(cos x − 1) = 2(1 + sin x) sin x + cos x cos x cot x = tan x + sin x (1 − sin x) cos x = (1 + 2sin x)(1 − sin x) 47/ sin x + cos x sin x + cos x = 2(cos x + sin x) cos x − 2sin x cos x − sin x = 49/ (1 + 2sin x) cos x = + sin x + cos x 1 7π 50/ + = 4sin( − x) sin x sin( x − 3π / 2) 48/