1) sinx =1/2 ;
x= π/6 +π*n ;n∈Z.
2) 2cos2x = -2;
cos2x = -1 ;
1+cos2x =0 ;
2cos²x =0 ;
cosx=0;
x =π/2+ π*n , n∈Z .
3) √2*sinx =1;
sinx =1/√2 ;
x = (-1)^(n)*π/4 +π* , n∈Z
4) sin2x =1 ;
2x =π/2+2π*n ,n∈Z ;
x = π/4 +π*n , n∈Z .
5) sin(x/2) =1;
x/2 =π/2+2π*n , n∈Z ;
x =π+4π*n , n∈Z .
6)2sin(x/2) = 1 ;
sin(x/2) =1/2;
x/2= π/6 +π*n ;n∈Z;
x= π/2 +2π*n ;n∈Z;
3x^2-5x-2=0
D=25+24=49=7^2
x1=(5+7)/12=12/12=1
x2=(5-7)/12= - 2/12= -1/6
<span>(3x-4)/2 - 1 = (3x-1)/7
(3x-6)/2=(3x-1)/7
21x-42=6x-2
15x=40
x=40/15=8/3</span>