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Question Number 144877 by imjagoll last updated on 30/Jun/21
  u+(√u)+(u)^(1/3) +(u)^(1/4) +(u)^(1/5) +... +∞=?
$$\:\:\mathrm{u}+\sqrt{\mathrm{u}}+\sqrt[{\mathrm{3}}]{\mathrm{u}}+\sqrt[{\mathrm{4}}]{\mathrm{u}}+\sqrt[{\mathrm{5}}]{\mathrm{u}}+…\:+\infty=? \\ $$$$ \\ $$
Answered by MJS_new last updated on 30/Jun/21
∀u>0:Σ_(n=1) ^∞ u^(1/n)  =+∞  easy to see because lim_(n→+∞) u^(1/n)  =1
$$\forall{u}>\mathrm{0}:\underset{{n}=\mathrm{1}} {\overset{\infty} {\sum}}{u}^{\mathrm{1}/{n}} \:=+\infty \\ $$$$\mathrm{easy}\:\mathrm{to}\:\mathrm{see}\:\mathrm{because}\:\underset{{n}\rightarrow+\infty} {\mathrm{lim}}{u}^{\mathrm{1}/{n}} \:=\mathrm{1} \\ $$
Commented by imjagoll last updated on 30/Jun/21
thank you sir
$$\mathrm{thank}\:\mathrm{you}\:\mathrm{sir} \\ $$

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