Find extrema of a two variable function

I want to find the extrema (max and minimun) of the next function, such that -2<=x<=2 and -2<=y<=2

(sqrt(40*(x.^2).*(y.^2) +164*x.^2 -152*(x.^2).*(y)+ 8.*x.*(y.^2)+ 156*x -120*x.*y +26*y.^2 -56*y +45))./(-4*(x.^2)+4*x+3)

But I dont get no conclusive result.

[Walter Roberson]

Can you use the symbolic toolbox?

Answer 1

[Walter Roberson]

The denominator can be 0 at two x values in that range, and the denominator can change sign. Depending on the sign of the denominator close to those two x, the value will approach arbitrarily close to +/- infinity.