Question

又是数学题！

ab=1，a+b=2，则式子：a分之b+b分之a=？

Answer 1

a分之b+b分之a
= (A^2 + B^2)/AB
= [(A + B)^2 - 2AB]/AB
代入A + B = 2，AB = 1，式子
= (2^2 - 2*1)/1
= 2

Answer 2

a/b+b/a
=(a²+b²)/ab
=[(a+b)²-2ab]/ab
=(4+2)/(-1)
=-6