后面没打上啊,是说乘以y^2吗?若是的话我想应该这么解
由已知可得（x^2-y^2)^2=x^2y^2,则x^4+y^4=3x^2y^2
x^2/y^2+y^2/x^2=(x^4+y^4)/x^2y^2=3x^2y^2/x^2y^2=3