Объяснение:
Вариант 2
1)cos(pi/6)cos(x) - sin(pi/6)sin(x) - ( (sqrt3 * cos(x) ) / 2 )
...
- (sin(x)/2)
2)sinxcosy + cosxsiny = sin(x+y)
sin(69+21) = sin(90) = 1
3)2sinxcosx = sin(2x)
sin(pi/6) = 1/2
5) a) sin(x) / 1 + cos(x) = tan(x/2)
tan(2x/2) = tan(x)
b) 2tan(x) / 1 - tan^2(x) = tan(2x)
tan(2x)*(1 + cos(4x))
