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Question-61907




Question Number 61907 by naka3546 last updated on 11/Jun/19
Commented by MJS last updated on 12/Jun/19
Σ_(n=1) ^∞ (1/n)=∞ ⇒ Σ_(n=1) ^∞ (1/( (n)^(1/k) ))=∞ for k∈N^★     calculating Ω_n  I get:  Ω_(125) ≈.849696  Ω_(250) ≈.846055  Ω_(500) ≈.843624  Ω_(1000) ≈.842011  Ω_(2000) ≈.840945
$$\underset{{n}=\mathrm{1}} {\overset{\infty} {\sum}}\frac{\mathrm{1}}{{n}}=\infty\:\Rightarrow\:\underset{{n}=\mathrm{1}} {\overset{\infty} {\sum}}\frac{\mathrm{1}}{\:\sqrt[{{k}}]{{n}}}=\infty\:\mathrm{for}\:{k}\in\mathbb{N}^{\bigstar} \\ $$$$ \\ $$$$\mathrm{calculating}\:\Omega_{{n}} \:\mathrm{I}\:\mathrm{get}: \\ $$$$\Omega_{\mathrm{125}} \approx.\mathrm{849696} \\ $$$$\Omega_{\mathrm{250}} \approx.\mathrm{846055} \\ $$$$\Omega_{\mathrm{500}} \approx.\mathrm{843624} \\ $$$$\Omega_{\mathrm{1000}} \approx.\mathrm{842011} \\ $$$$\Omega_{\mathrm{2000}} \approx.\mathrm{840945} \\ $$
Answered by tanmay last updated on 11/Jun/19
lim_(n→∞)  (N_r /D_r )  N_r =[((1/1))^(1/5) +((1/2))^(1/5) +((1/3))^(1/5) +...+((1/n))^(1/5) ]^(2/3)   D_r =[((1/1))^(1/3) +((1/2))^(1/3) +((1/3))^(1/3) +...+((1/n))^(1/3) ]^(4/5)   N_r =[((1/1))^(1/5) +((1/2))^(1/5) +((1/3))^(1/5) +...+((1/n))^(1/5) ]^((10)/(15))   D_r =[((1/1))^(1/3) +((1/2))^(1/3) +((1/3))^(1/3) +...+((1/n))^(1/3) ]^((12)/(15))   N_r =[{((1/1))^(1/5) +((1/2))^(1/5) +((1/3))^(1/5) +...+((1/n))^(1/5) }^5 ]^(2/(15))   =Σ_(n=1) ^n [{((1/n))^(1/5) }^5 ]^(2/(15))  and D_r =Σ_(n=1) ^∞ [{((1/n))^(1/3) }^6 ]^(2/(15))   N_r =[(1/1)+(1/2)+..+(1/n)+g(n)]^(2/(15))   D_r =[(1/1^2 )+(1/2^2 )+..+(1/n^2 )+h(n)]^(2/(15))   (1/n^2 )<(1/n)    D_r <N_r   wait...
$$\underset{{n}\rightarrow\infty} {\mathrm{lim}}\:\frac{{N}_{{r}} }{{D}_{{r}} } \\ $$$${N}_{{r}} =\left[\left(\frac{\mathrm{1}}{\mathrm{1}}\right)^{\frac{\mathrm{1}}{\mathrm{5}}} +\left(\frac{\mathrm{1}}{\mathrm{2}}\right)^{\frac{\mathrm{1}}{\mathrm{5}}} +\left(\frac{\mathrm{1}}{\mathrm{3}}\right)^{\frac{\mathrm{1}}{\mathrm{5}}} +…+\left(\frac{\mathrm{1}}{{n}}\right)^{\frac{\mathrm{1}}{\mathrm{5}}} \right]^{\frac{\mathrm{2}}{\mathrm{3}}} \\ $$$${D}_{{r}} =\left[\left(\frac{\mathrm{1}}{\mathrm{1}}\right)^{\frac{\mathrm{1}}{\mathrm{3}}} +\left(\frac{\mathrm{1}}{\mathrm{2}}\right)^{\frac{\mathrm{1}}{\mathrm{3}}} +\left(\frac{\mathrm{1}}{\mathrm{3}}\right)^{\frac{\mathrm{1}}{\mathrm{3}}} +…+\left(\frac{\mathrm{1}}{{n}}\right)^{\frac{\mathrm{1}}{\mathrm{3}}} \right]^{\frac{\mathrm{4}}{\mathrm{5}}} \\ $$$${N}_{{r}} =\left[\left(\frac{\mathrm{1}}{\mathrm{1}}\right)^{\frac{\mathrm{1}}{\mathrm{5}}} +\left(\frac{\mathrm{1}}{\mathrm{2}}\right)^{\frac{\mathrm{1}}{\mathrm{5}}} +\left(\frac{\mathrm{1}}{\mathrm{3}}\right)^{\frac{\mathrm{1}}{\mathrm{5}}} +…+\left(\frac{\mathrm{1}}{{n}}\right)^{\frac{\mathrm{1}}{\mathrm{5}}} \right]^{\frac{\mathrm{10}}{\mathrm{15}}} \\ $$$${D}_{{r}} =\left[\left(\frac{\mathrm{1}}{\mathrm{1}}\right)^{\frac{\mathrm{1}}{\mathrm{3}}} +\left(\frac{\mathrm{1}}{\mathrm{2}}\right)^{\frac{\mathrm{1}}{\mathrm{3}}} +\left(\frac{\mathrm{1}}{\mathrm{3}}\right)^{\frac{\mathrm{1}}{\mathrm{3}}} +…+\left(\frac{\mathrm{1}}{{n}}\right)^{\frac{\mathrm{1}}{\mathrm{3}}} \right]^{\frac{\mathrm{12}}{\mathrm{15}}} \\ $$$${N}_{{r}} =\left[\left\{\left(\frac{\mathrm{1}}{\mathrm{1}}\right)^{\frac{\mathrm{1}}{\mathrm{5}}} +\left(\frac{\mathrm{1}}{\mathrm{2}}\right)^{\frac{\mathrm{1}}{\mathrm{5}}} +\left(\frac{\mathrm{1}}{\mathrm{3}}\right)^{\frac{\mathrm{1}}{\mathrm{5}}} +…+\left(\frac{\mathrm{1}}{{n}}\right)^{\frac{\mathrm{1}}{\mathrm{5}}} \right\}^{\mathrm{5}} \right]^{\frac{\mathrm{2}}{\mathrm{15}}} \\ $$$$=\underset{{n}=\mathrm{1}} {\overset{{n}} {\sum}}\left[\left\{\left(\frac{\mathrm{1}}{{n}}\right)^{\frac{\mathrm{1}}{\mathrm{5}}} \right\}^{\mathrm{5}} \right]^{\frac{\mathrm{2}}{\mathrm{15}}} \:{and}\:{D}_{{r}} =\underset{{n}=\mathrm{1}} {\overset{\infty} {\sum}}\left[\left\{\left(\frac{\mathrm{1}}{{n}}\right)^{\frac{\mathrm{1}}{\mathrm{3}}} \right\}^{\mathrm{6}} \right]^{\frac{\mathrm{2}}{\mathrm{15}}} \\ $$$${N}_{{r}} =\left[\frac{\mathrm{1}}{\mathrm{1}}+\frac{\mathrm{1}}{\mathrm{2}}+..+\frac{\mathrm{1}}{{n}}+{g}\left({n}\right)\right]^{\frac{\mathrm{2}}{\mathrm{15}}} \\ $$$${D}_{{r}} =\left[\frac{\mathrm{1}}{\mathrm{1}^{\mathrm{2}} }+\frac{\mathrm{1}}{\mathrm{2}^{\mathrm{2}} }+..+\frac{\mathrm{1}}{{n}^{\mathrm{2}} }+{h}\left({n}\right)\right]^{\frac{\mathrm{2}}{\mathrm{15}}} \\ $$$$\frac{\mathrm{1}}{{n}^{\mathrm{2}} }<\frac{\mathrm{1}}{{n}}\:\:\:\:{D}_{{r}} <{N}_{{r}} \\ $$$${wait}… \\ $$$$ \\ $$

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