求下列函数的极限 求下列函数的极限 lim(x→∞){1+e^(-x)} ; lim(x→1){|x-1|/(x-1)}

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求下列函数的极限 求下列函数的极限 lim(x→∞){1+e^(-x)} ; lim(x→1){|x-1|/(x-1)}

求下列函数的极限 求下列函数的极限 lim(x→∞){1+e^(-x)} ; lim(x→1){|x-1|/(x-1)}
求下列函数的极限 求下列函数的极限 lim(x→∞){1+e^(-x)} ; lim(x→1){|x-1|/(x-1)}

求下列函数的极限 求下列函数的极限 lim(x→∞){1+e^(-x)} ; lim(x→1){|x-1|/(x-1)}
(1)lim(x→∞){1+e^(-x)}
当x→+∞时,e^(-x)趋于0,因此上述极限趋于1
当x→-∞时,e^(-x)趋于+∞,因此上述极限趋于+∞
故lim(x→∞){1+e^(-x)}不存在
(2)lim(x→1){|x-1|/(x-1)}
lim(x→1+){|x-1|/(x-1)}= lim(x→1){(x-1)/(x-1)}=1
lim(x→1-){|x-1|/(x-1)}= lim(x→1){-(x-1)/(x-1)}=-1
因此 lim(x→1){|x-1|/(x-1)}不存在

1
不存在

lim(x→+∞){1+e^(-x)} = 1;
lim(x→-∞){1+e^(-x)} = 无极限
lim(x→1+) {|x-1|/(x-1)} = lim(x→1+){(x-1)/(x-1)} = 1;
lim(x→1-) {|x-1|/(x-1)} = lim(x→1+){-(x-1)/(x-1)} = -1;