Question

先化简，在求值：a^2-1/a-1-根号a^2-2a+1/a^2-a,其中a=1/2+根号3

Answer 1

Answer 2

分母有理化
a=2-√3
则a-1<0
|a-1|=-(a-1)
且1/a=2+√3

原式=(a+1)(a-1)/(a-1)-√(a-1)²/a(a-1)
=a+1-|a-1|/a(a-1)
=a+1+1/a
=2-√3+1+2+√3
=5