First find the critical points of <em>f</em> :
so the point (1, 0) is the only critical point, at which we have
Next check for critical points along the boundary, which can be found by converting to polar coordinates:
Find the critical points of <em>g</em> :
where <em>n</em> is any integer. We get 4 critical points in the interval [0, 2π) at
So <em>f</em> has a minimum of -7 and a maximum of 299.