已知x=7+4根号3,y=7-4根号3,求x/y+y/x的值
问题描述：
已知x=7+4根号3,y=7-4根号3,求x/y+y/x的值
答
已知x=7+4根号3,y=7-4根号3,
x/y+y/x
=(x²+y²)/(xy)
=[(x+y)²-2xy]/(xy)
=[14²-2×(7+4√3)×(7-4√3)]/(7+4√3)(7-4√3)
=(196-2)/2
=97;