分式计算!先化简 再求值.

问题描述:

分式计算!先化简 再求值.
{3a/(a-1)-2/(a+1)*(a^2-1)/a 其中a=根号3

=3a/(a-1)-2/(a+1)*(a-1)(a+1)/a
=3a/(a-1)-2a/(a-1)
=a/(a-1)
=根号3(根号3+1)/2