[tex](sin x +3cosy)^2 + (cos x-3siny)^2 = 10 \\[/tex] si x,y ∈(0,π/2), atunci x=y
![Texsin X 3cosy2 Cos X3siny2 10 Tex Si Xy 0π2 Atunci Xy class=](https://ro-static.z-dn.net/files/dbc/94cba52ec63a3c03fd1f3b8e98ea2999.jpg)
Răspuns:
Explicație pas cu pas:
sin²x+6sinxcosy+9cos²y+cos²x-6sinycosx+9siny²=10
1+9+6sinxcosy-6sinycosx=10
sinxcosy-siny cosx=0
sin(x-y)=0
x-y=kπ
dar 0 nu apartine dom dedef
ramane
sinx=cosx=siny=cosy
x=y=π/4