limx->无限 [x^2/(x^2+1)]^x=?

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limx->无限 [x^2/(x^2+1)]^x=?

答:
lim [x^2/(x^2+1)]^x
=lim [1-1/(x^2+1)]^x
=lim (1-1/x^2)^x
=lim {[(1-1/x)^(-x)*(-1)]*(1+1/x)^x} x→∞
=(1/e)*e
=1

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