根号a2-4a+1+(1-4b+4b2)=O,
a2-4a+1=0,同除以a a-4+1/a=0 a+1/a=4 1-4b+4b2=0=（2b-1)^2 2b-1=0 b=1/2
a2+1/a2+b=(a+1/a)^2-2+1/2=4^2-2+1/2=14.5