Question

先化简,再求值:(1-2a+a2)/(a-1)-(根号a2-2a+1)/(a2-a)-(1/a)+(根号a2),a=2-根号3

在线等，，快

Answer 1

0<a=2-根号3<1
根号(a2-2a+1)=1-a
(1-2a+a^2)/(a-1)-根号(a^2-2a+1)/(a^2-a)-(1/a)+(根号a^2)
=(a-1)^2/(a-1)-(1-a)/[a*(a-1)]-(1/a)+a
=a-1+1/a-1/a+a
=2a-1
=3-2倍根号3