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