B
boydeptrai102


giải các pt lượng giác sau :
1/ sin x * sin 2x + sin 3X = 6 *[ (cos x )^3]
2/ [cos x * cos x/2 * cos 3x/2 ]- [sin x * sin x/2 * sin 3x/2 ]=1/2
3/ [[sqrt(2)]* cos(x/5 - pi/12)] - [ [ sqrt(6)] * sin ( x/5 - pi/12)] = 2*sin(x/5 + 2*pi/3) - 2*sin(3x/5 + pi/6)
4/[(sin 2x)^3]* cos 6x + sin 6x * [(cos 2x )^3] = 3/8
1/ sin x * sin 2x + sin 3X = 6 *[ (cos x )^3]
2/ [cos x * cos x/2 * cos 3x/2 ]- [sin x * sin x/2 * sin 3x/2 ]=1/2
3/ [[sqrt(2)]* cos(x/5 - pi/12)] - [ [ sqrt(6)] * sin ( x/5 - pi/12)] = 2*sin(x/5 + 2*pi/3) - 2*sin(3x/5 + pi/6)
4/[(sin 2x)^3]* cos 6x + sin 6x * [(cos 2x )^3] = 3/8