F.4 m2 about limit~3

lim x→∞ [√(x^2 + x)－2√(x^2 + 2x) +x]


=lim x→∞ [√(x^2+x+1/4)－2√(x^2 + 2x+1) +x]

=lim x→∞ [(x+1/2)－2(x+1)+x]

=lim x→∞ [－3/2]

=－3/2

Here are the steps:

圖片參考：http://imgcld.yimg.com/8/n/HA00238614/o/701004110103213873382490.jpg