lim(x→0) [√(x+1)-1]/x
=lim(x→0) [√(x+1)-1] [√(x+1)+1]/x [√(x+1)+1]
= lim(x→0) x/x [√(x+1)+1]
= lim(x→0) 1/ [√(x+1)+1]
=1/(√(0+1)+1)
=1/2