√2*cos(2x)=cos(x)+sin(x)
(√2*cos(2x))²=(cos(x)+sin(x))²
2*cos²(2x)=cos²(x)+2*sin(x)*cos(x)+sin²(x)
2*(1-sin²(2x))=1+sin(2x)
2-2*sin²(2x)=1+sin(2x)
2*sin²(2x)+sin(2x)-1=0
Пусть sin(2x)=t ⇒
2t²+t-1=0 D=9 √D=3
t₁=sin(2x)=-1 2x=3π/2+2πn x₁=3π/4+πn
t₂=sin(2x)=1/2 2x=π/6+2πn x₂=π/12+πn
2x=5π/6+2πn x₃=5π/12+πn.
2. х=-0.8; 0.8
3. у= 0;
4. х= 2; -2
5. z= -
6. х= 0;
7. у=
8. z=-
9. х=-
10. х=0;