求极限,要明细哦求极限(要明细哦)

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求极限,要明细哦

求极限(要明细哦)

lim(x->∞) [(x+5)/(x+2)] ^(x+3)
=lim(x->∞) [1+ 3/(x+2)] ^[(x+2)/3 * 3(x+3)/(x+2)]
=lim(x->∞) {[1+ 3/(x+2)] ^(x+2)/3 } ^ 3(x+3)/(x+2)
显然在x趋于∞的时候,
[1+ 3/(x+2)] ^(x+2)/3的极限值为e,
而3(x+3)/(x+2)的极限值为3,
所以
原极限
=lim(x->∞) {[1+ 3/(x+2)] ^(x+2)/3 } ^ 3(x+3)/(x+2)
=e^3