б) sinx=y;
IyI≤1;
2y²-5y+2=0;
y=(5±√(25-16))/4=(5±3)/2? y=2>1, ∅; у=-2/4=-1/2;
sinx=-1/2; х=(-1)ⁿarcsin(-1/2)+πk; k∈Z; х=(-1)ⁿ⁺¹arcsin(1/2)+πk; k∈Z;
х=(-1)ⁿ⁺¹π/6+πk; k∈Z;
г) 4cos²x-4cosx+1=0
(2cosx-1)²=0;
cosx=y;
2y-1=0; 2y=1;
y=1/2;
cosx=1/2;
x=±arccos(1/2)+2πn; n∈Z
х=±π/3+2πn; n∈Z
б) sinx=y;
IyI≤1;
2y²-5y+2=0;
y=(5±√(25-16))/4=(5±3)/2? y=2>1, ∅; у=-2/4=-1/2;
sinx=-1/2; х=(-1)ⁿarcsin(-1/2)+πk; k∈Z; х=(-1)ⁿ⁺¹arcsin(1/2)+πk; k∈Z;
х=(-1)ⁿ⁺¹π/6+πk; k∈Z;
г) 4cos²x-4cosx+1=0
(2cosx-1)²=0;
cosx=y;
IyI≤1;
2y-1=0; 2y=1;
y=1/2;
cosx=1/2;
x=±arccos(1/2)+2πn; n∈Z
х=±π/3+2πn; n∈Z