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极限问题,求帮忙
1个回答
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解:
令x=1/t,则1/x=t
x→+∞,则t→0⁺
lim [x- x²ln(1+ 1/x)]
x→+∞
=lim [1/t -(1/t²)ln(1+t)]
t→0⁺
=lim[ [t -ln(1+t)]/t²
t→0⁺
=lim [1- 1/(1+t)]/(2t)
t→0⁺
=lim [t/(1+t)]/(2t)
t→0⁺
=lim 1/(2t+2)
t→0⁺
=1/(2·0+2)
=1/2
令x=1/t,则1/x=t
x→+∞,则t→0⁺
lim [x- x²ln(1+ 1/x)]
x→+∞
=lim [1/t -(1/t²)ln(1+t)]
t→0⁺
=lim[ [t -ln(1+t)]/t²
t→0⁺
=lim [1- 1/(1+t)]/(2t)
t→0⁺
=lim [t/(1+t)]/(2t)
t→0⁺
=lim 1/(2t+2)
t→0⁺
=1/(2·0+2)
=1/2
追问
不用洛必达能做吗?
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