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lim-x-1-e-x-1-x-1-x-1-




Question Number 172910 by DAVONG last updated on 03/Jul/22
lim_(x→1) ((e−x^(1/(x−1)) )/(x−1))=?
limx1ex1x1x1=?
Answered by FongXD last updated on 03/Jul/22
L=lim_(x→1) ((e−e^((1/(x−1))lnx) )/(x−1))=−lim_(x→1) ((e(e^(((lnx)/(x−1))−1) −1))/(((lnx)/(x−1))−1))×((((lnx)/(x−1))−1)/(x−1))  L=−elim_(x→1) ((lnx−x+1)/((x−1)^2 ))  put x=e^t , if x→1, ⇒ t→0  then L=−elim_(t→0) ((t−e^t +1)/((e^t −1)^2 ))=elim_(t→0) ((e^t −t−1)/t^2 )×((t/(e^t −1)))^2   L=elim_(t→0) ((e^t −t−1)/t^2 )=(e/4)lim_(u→0) ((e^(2u) −2u−1)/u^2 ), [t=2u]  L−(e/4)=(e/4)lim_(u→0) ((e^(2u) −u^2 −2u−1)/u^2 )=(e/4)lim_(u→0) ((e^(2u) −(u+1)^2 )/u^2 )  L−(e/4)=(e/4)lim_(u→0) ((e^u −u−1)/u^2 )(e^u +u+1)  L−(e/4)=(1/4)L×2=(1/2)L  L=(e/2)
L=limx1ee1x1lnxx1=limx1e(elnxx111)lnxx11×lnxx11x1L=elimx1lnxx+1(x1)2putx=et,ifx1,t0thenL=elimt0tet+1(et1)2=elimt0ett1t2×(tet1)2L=elimt0ett1t2=e4limu0e2u2u1u2,[t=2u]Le4=e4limu0e2uu22u1u2=e4limu0e2u(u+1)2u2Le4=e4limu0euu1u2(eu+u+1)Le4=14L×2=12LL=e2

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