已知a+b=3,ab=0.5,求a/b+b/a
问题描述:
已知a+b=3,ab=0.5,求a/b+b/a
答
a/b+b/a
=a²/ab+b²/ab
=(a²+b²)/ab
=(a²+b²+2ab-2ab)/ab
=[(a+b)²-2ab]/ab
=(3²-2×0.5)/0.5
=(9-1)/0.5
=16