若a+b=1a^2+b^2=2则b/a+a/b=?thankyou!

Question

若a+b=1 a^2+b^2=2 则b/a+a/b=? thank you!

Answer 1

(a+b)^2=1 a^2+b^2=2
ab=-1/2
b/a+a/b=(a^2+b^2)/ab=2/(-1/2)=-4