|√(n+1)-√n -0| < ε|1/(√(n+1) + √n )| < ε1/(2√n) < εn > { 1/(2ε) }^2∀ε>0 ,∃N = [{ 1/(2ε) }^2] +1, st|√(n+1)-√n -0| < ε , ∀N>n=>lim(n->∞) [√(n+1)-√n]=0其余类似
