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Question Number 205916 by mathzup last updated on 02/Apr/24

lim_(x→0^+ )   xln(e^x −1)

limx0+xln(ex1)

Answered by mathzup last updated on 03/Apr/24

lim_(x→0^+ )   xln(e^x −1)  =lim_(x→0^+ )   x{ln(e^x −1)−lnx +lnx}  =lim_(x→0^+ )   xln(((e^x −1)/x))+xlnx  lim_(x→0^+ )   xln(((e^x −1)/x))=0.ln(1)=0  lim_(x→0^+ )   xlnx =0 ⇒  lim_(x→0) xln(e^x −1)=0

limx0+xln(ex1)=limx0+x{ln(ex1)lnx+lnx}=limx0+xln(ex1x)+xlnxlimx0+xln(ex1x)=0.ln(1)=0limx0+xlnx=0limx0xln(ex1)=0

Commented by mathzup last updated on 03/Apr/24

another way we do the changement  e^x −1=t ⇒e^x =1+t and x=ln(1+t)  x→0 ⇔t→0 and  lim_(x→0^+ )  xln(e^x −1)=lim_(t→0)  ln(1+t)lnt  =lim_(t→0) ((ln(1+t))/t)×lim_(t→0) tlnt  =1×0=0

anotherwaywedothechangementex1=tex=1+tandx=ln(1+t)x0t0andlimx0+xln(ex1)=limt0ln(1+t)lnt=limt0ln(1+t)t×limt0tlnt=1×0=0

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