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Category: Relation and Functions

find-radius-and-sum-of-n-0-x-2n-2n-1-2-find-n-0-1-2n-1-9-n-

Question Number 29981 by abdo imad last updated on 14/Feb/18 $${find}\:{radius}\:{and}\:{sum}\:{of}\:\:\:\sum_{{n}=\mathrm{0}} ^{\infty} \:\:\:\:\frac{{x}^{\mathrm{2}{n}} }{\mathrm{2}{n}+\mathrm{1}} \\ $$$$\left.\mathrm{2}\right)\:{find}\:\:\:\sum_{{n}=\mathrm{0}} ^{\infty} \:\:\:\:\:\frac{\mathrm{1}}{\left(\mathrm{2}{n}+\mathrm{1}\right)\mathrm{9}^{{n}} }\:. \\ $$ Commented by abdo imad…

let-give-x-gt-0-1-prove-that-0-1-dt-1-t-x-n-0-1-n-nx-1-2-find-n-0-1-n-n-1-and-n-0-1-n-2n-1-3-find-n-1-1-n-

Question Number 29978 by abdo imad last updated on 14/Feb/18 $${let}\:{give}\:{x}>\mathrm{0} \\ $$$$\left.\mathrm{1}\right)\:{prove}\:{that}\:\:\:\int_{\mathrm{0}} ^{\mathrm{1}} \:\:\:\:\frac{{dt}}{\mathrm{1}+{t}^{{x}} }=\:\sum_{{n}=\mathrm{0}} ^{\infty} \:\:\:\frac{\left(−\mathrm{1}\right)^{{n}} }{{nx}+\mathrm{1}} \\ $$$$\left.\mathrm{2}\right)\:{find}\:\sum_{{n}=\mathrm{0}} ^{\infty} \:\:\frac{\left(−\mathrm{1}\right)^{{n}} }{{n}+\mathrm{1}}\:\:{and}\:\sum_{{n}=\mathrm{0}} ^{\infty}…

find-the-radius-of-S-x-n-0-x-3n-2-3n-2-2-find-the-value-of-n-0-1-3n-2-3-n-

Question Number 29979 by abdo imad last updated on 14/Feb/18 $${find}\:{the}\:{radius}\:{of}\:{S}\left({x}\right)=\:\sum_{{n}=\mathrm{0}} ^{\infty} \:\:\:\frac{{x}^{\mathrm{3}{n}+\mathrm{2}} }{\mathrm{3}{n}+\mathrm{2}} \\ $$$$\left.\mathrm{2}\right){find}\:{the}\:{value}\:{of}\:\:\sum_{{n}=\mathrm{0}} ^{\infty} \:\:\:\frac{\mathrm{1}}{\left(\mathrm{3}{n}+\mathrm{2}\right)\mathrm{3}^{{n}} }. \\ $$ Commented by abdo imad…

give-the-developpement-at-integr-series-for-f-x-ln-1-x-ln-1-x-x-2-find-lim-x-0-f-x-

Question Number 29846 by abdo imad last updated on 12/Feb/18 $${give}\:{the}\:{developpement}\:\:{at}\:{integr}\:{series}\:{for} \\ $$$${f}\left({x}\right)=\frac{{ln}\left(\mathrm{1}+{x}\right)−{ln}\left(\mathrm{1}−{x}\right)}{{x}} \\ $$$$\left.\mathrm{2}\right){find}\:\:\:{lim}_{{x}\rightarrow\mathrm{0}} \:{f}\left({x}\right). \\ $$ Commented by maxmathsup by imad last updated…

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Question Number 29844 by abdo imad last updated on 12/Feb/18 $${let}\:{give}\:{f}_{\alpha} \left({t}\right)={cos}\left(\alpha{t}\right)\:\:\mathrm{2}\pi\:{periodic}\:{with}\:{t}\:\in\left[−\pi,\pi\right]{and} \\ $$$$\alpha\in\:{R}−{Z} \\ $$$$\left.\mathrm{1}\right)\:{developp}\:{f}_{\alpha} \:\:{at}\:{fourier}\:{serie}\:{and}\:{prove}\:{that} \\ $$$${cotan}\left(\alpha\pi\right)=\:\frac{\mathrm{1}}{\alpha\pi}\:\:+\sum_{{n}=\mathrm{1}} ^{\infty} \:\:\frac{\mathrm{2}\alpha}{\pi\left(\alpha^{\mathrm{2}} −{n}^{\mathrm{2}} \right)} \\ $$$$\left.\mathrm{2}\left.\right)\left.{let}\:{x}\in\right]\mathrm{0},\pi\left[\:{ant}\:{g}\left({t}\right)={cotant}\:−\frac{\mathrm{1}}{{t}}\:\:{if}\:{t}\in\right]\mathrm{0},{x}\right]{andg}\left(\mathrm{0}\right)=\mathrm{0}…