Please, help me with this. I have no idea how to solve it

In what points are the tangent to the ellipse parallel to the line y = x?

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- Nov 24th 2008, 11:57 AMPommacFinding the points
Please, help me with this. I have no idea how to solve it

In what points are the tangent to the ellipse parallel to the line y = x? - Nov 24th 2008, 04:30 PMskeeter
why are the coefficients written that way?

why not just $\displaystyle 13x^2 - 12xy + 13y^2 = 2$ ?

in any case, find $\displaystyle \frac{dy}{dx}$ implicitly and set it equal to 1.

solve for x in terms of y or y in terms of x (whichever is easier), and sub the result back into the original equation to solve for the that chosen variable.