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lim-x-2-sin-x-lnx-




Question Number 78828 by john santu last updated on 21/Jan/20
lim_(x→∞)  (2+sin x).lnx = ?
$$\underset{{x}\rightarrow\infty} {\mathrm{lim}}\:\left(\mathrm{2}+\mathrm{sin}\:{x}\right).{lnx}\:=\:? \\ $$
Commented by mr W last updated on 21/Jan/20
(2+sin x).lnx >ln x  lim_(x→∞) (2+sin x).lnx >lim_(x→∞) ln x=∞  ⇒lim_(x→∞) (2+sin x).lnx =∞
$$\left(\mathrm{2}+\mathrm{sin}\:{x}\right).{lnx}\:>\mathrm{ln}\:{x} \\ $$$$\underset{{x}\rightarrow\infty} {\mathrm{lim}}\left(\mathrm{2}+\mathrm{sin}\:{x}\right).{lnx}\:>\underset{{x}\rightarrow\infty} {\mathrm{lim}ln}\:{x}=\infty \\ $$$$\Rightarrow\underset{{x}\rightarrow\infty} {\mathrm{lim}}\left(\mathrm{2}+\mathrm{sin}\:{x}\right).{lnx}\:=\infty \\ $$
Commented by john santu last updated on 21/Jan/20
sir in my book , the answer is   ln 3. i′m can′t get it
$${sir}\:{in}\:{my}\:{book}\:,\:{the}\:{answer}\:{is}\: \\ $$$${ln}\:\mathrm{3}.\:{i}'{m}\:{can}'{t}\:{get}\:{it} \\ $$
Commented by mr W last updated on 21/Jan/20
either the question is wrong or the  answer in your book is wrong.
$${either}\:{the}\:{question}\:{is}\:{wrong}\:{or}\:{the} \\ $$$${answer}\:{in}\:{your}\:{book}\:{is}\:{wrong}. \\ $$

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