Question

1.若1/a+1/b=1/(a+b),则b/a+a/b的值为?

Answer 1

1/a+1/b=(a+b)/(ab)=1/(a+b)

ab=(a+b)2

ab=a2+2ab+b2

a2+b2 =-ab

b/a+a/b=(b2+a2)/(ab)=-ab/ab=-1

第二题

s/a=v1-v2

s/b=v1+v2

v1=(1/a+1/b)*(s/2)

v2=(1/b-1/a)*(s/2)

v1/v2=(a+b)/(a-b)