Question

已知x^2+xy-2y^2=0 (x不等于0,y不等于0）,求x/y-y/x-(x^2+y^2)/xy的值

Answer 1

因为x^2+xy-2y^2=0

所以x=-2y x=y

(1)x=-2y

所以

x/y-y/x-(x^2+y^2)/xy

=-2+1/2+5/2=1

(2)x=y

x/y-y/x-(x^2+y^2)/xy

=1-1-2=-2