Find the lengths of the semi-axes of the ellipse: $5x^2 −8xy + 5y^2 = 1$.
My Try : I know I have to get two Perpendicular straight lines $L_1$ and $L_2$ such that $L_1^2 + L_2^2 = 5x^2 −8xy + 5y^2 = 1$. But I can not do it.
Can anyone please help me.