1)2sin²x+3sinx-2=0
sinx=z
2z²+3z-2=0,D=9+16=25,√D=√25=2
z1=(-3+2)/2=-1/2
z2=(-3-2)/2=-5/2=-2,5 ne dact rešenie
sinx=-1/2
a)x=7π/6+2kπ
b)x=11π/6+2kπ, k∈Z
2)2cos²x-5cosx-3=0
cosx=z
2z²-5z-3=0,D=25+24=49,√D=√49=7
z1=(5+7)/4=12/4=3, ne dact rešenie
z2=(5-7)/4=-2/4=-1/2
cosx=-1/2
a)x=2π/3+2kπ
b)x=4π/3+2kπ, k∈Z
3)tg²x-4tgx+3=0
tgx=z
z²-4z+3=0,D=16-12=4,√D=√4=2
z1=(4+2)/2=6/2=3
z2=(4-2)/2=2/2=1
a)tgx=3, x=arctg 3 +kπ
b)tgx=1, x=π/4+kπ, k∈Z