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Category: Relation and Functions

find-the-range-of-f-x-1-2x-1-

Question Number 32489 by NECx last updated on 26/Mar/18 $${find}\:{the}\:{range}\:{of}\:{f}\left({x}\right)=\mathrm{1}+\sqrt{\mathrm{2}{x}−\mathrm{1}} \\ $$ Commented by prof Abdo imad last updated on 28/Mar/18 $${D}_{{f}} =\left[\frac{\mathrm{1}}{\mathrm{2}},+\infty\left[\:\:{and}\:{f}^{'} \left({x}\right)\:=\:\:\frac{\mathrm{1}}{\:\sqrt{\mathrm{2}{x}−\mathrm{1}}}\:\:>\mathrm{0}\:{on}\right]\frac{\mathrm{1}}{\mathrm{2}},+\infty\left[\right.\right. \\…

let-x-gt-1-and-x-n-1-1-n-x-zeta-function-of-Rieman-1-calculate-lim-x-x-2-let-consider-s-x-n-2-n-n-x-n-study-the-convergence-of-s-x-and-find-a-simple-form

Question Number 32487 by abdo imad last updated on 25/Mar/18 $${let}\:{x}>\mathrm{1}\:{and}\:\xi\left({x}\right)\:=\sum_{{n}=\mathrm{1}} ^{\infty} \:\:\frac{\mathrm{1}}{{n}^{{x}} }\:\left({zeta}\:{function}\:{of}\:{Rieman}\right) \\ $$$$\left.\mathrm{1}\right)\:{calculate}\:{lim}_{{x}\rightarrow+\infty} \xi\left({x}\right) \\ $$$$\left.\mathrm{2}\right){let}\:{consider}\:\:{s}\left({x}\right)=\sum_{{n}=\mathrm{2}} ^{\infty} \:\:\frac{\xi\left({n}\right)}{{n}}\:{x}^{{n}} \:{study}\:{the}\:{convergence} \\ $$$${of}\:{s}\left({x}\right)\:{and}\:{find}\:{a}\:{simple}\:{form}\:{of}\:{s}\left({x}\right). \\…