решить:
3tg(-П/4) + 2sin П/4 - 3tg 0 - 2ctg П/4= -3 + 2·√2/2 - 0 - 2= -5+√2
2sin^2 x - 3sin x + 1 = 0 sin x=t
2t²-3t+1=0
t1=(3-√(9-8) )/4=1/2 t2=(3+√(9-8) )/4=1
sin x=1/2 x=(-1)ⁿπ/6+πn, n∈Z
sin x=1 x=π/2+2πn, n∈Z
2cos^2 x - sin x - 1 = 0
2(1-sin² x ) - sin x - 1 = 0 1-2sin² x - sin x=0 sin x=t
2t²+t-1=0 t1=( -1-√(1+8))/4= -1 t2=( -1+√(1+8))/4=1/2
sin x= -1 x=-π/2+2πn, n∈Z
sin x=1/2 x=(-1)ⁿπ/6+πn, n∈Z