題目 Problem Find the absolute maximum value and absolute minimum value of f(x,y)=x4+y4−4xy+1f(x,y)=x^4+y^4-4xy+1f(x,y)=x4+y4−4xy+1 on the disk x2+y2≤1x^2+y^2\le 1x2+y2≤1. 解答
