如果分子极限不等于零,直接代入,如:
lim[x→1](x+2)/(2x-1)
=(1+2)/(2*1-1)
=3/1=3
如果分子、分母极限都等于零,消去零因子,如:
lim[x→1](x-1)/(x^2-1)
=lim[x→1](x-1)/[(x-1)(x+1)]
=lim[x→1]1)/(x+1)
=1/2
如果分子极限不等于零,直接代入,如:
lim[x→1](x+2)/(2x-1)
=(1+2)/(2*1-1)
=3/1=3
如果分子、分母极限都等于零,消去零因子,如:
lim[x→1](x-1)/(x^2-1)
=lim[x→1](x-1)/[(x-1)(x+1)]
=lim[x→1]1)/(x+1)
=1/2