极限lim(x趋近于∞)[e^x-e^(-x)]/[e^x+e^(-x)]等于多少?

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极限lim(x趋近于∞)[e^x-e^(-x)]/[e^x+e^(-x)]等于多少?
极限lim(x趋近于∞)[e^x-e^(-x)]/[e^x+e^(-x)]等于多少?

极限lim(x趋近于∞)[e^x-e^(-x)]/[e^x+e^(-x)]等于多少?
lim(x趋近于∞)[e^x-e^(-x)]/[e^x+e^(-x)]
=lim(x趋近于∞)[1-e^(-2x)]/[1+e^(-2x)]
=(1-0)/(1+0)
=1

1

lim(x趋近于+∞)[e^x-e^(-x)]/[e^x+e^(-x)]
=lim(x趋近于+∞)e^x/e^x
=1
lim(x趋近于-∞)[e^x-e^(-x)]/[e^x+e^(-x)]
=lim(x趋近于-∞)-e^(-x)/e^(-x)
=-1
所以极限不存在!!!