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Category: Relation and Functions

find-all-function-f-R-R-such-that-x-y-R-f-x-f-y-f-f-y-xf-y-f-x-1-

Question Number 194688 by CrispyXYZ last updated on 13/Jul/23 $$\mathrm{find}\:\mathrm{all}\:\mathrm{function}\:{f}:\:\mathbb{R}\:\rightarrow\:\mathbb{R}\:\mathrm{such}\:\mathrm{that}\:\forall{x},\:{y}\in\mathbb{R}, \\ $$$${f}\left({x}−{f}\left({y}\right)\right)={f}\left({f}\left({y}\right)\right)+{xf}\left({y}\right)+{f}\left({x}\right)−\mathrm{1}. \\ $$ Answered by Tinku Tara last updated on 13/Jul/23 $${put}\:{x}={f}\left({y}\right) \\ $$$${f}\left(\mathrm{0}\right)={f}\left({x}\right)+{x}^{\mathrm{2}}…

Question-193267

Question Number 193267 by Mingma last updated on 09/Jun/23 Answered by cortano12 last updated on 09/Jun/23 $$\:\:\left(\mathrm{i}\right)\:\mathrm{4f}\left(\mathrm{x}\right)+\mathrm{f}\left(\frac{\mathrm{1}}{\mathrm{x}}\right)=\mathrm{24x}+\mathrm{5}+\frac{\mathrm{6}}{\mathrm{x}} \\ $$$$\:\:\left(\mathrm{ii}\right)\:\mathrm{4f}\left(\frac{\mathrm{1}}{\mathrm{x}}\right)+\mathrm{f}\left(\mathrm{x}\right)=\frac{\mathrm{24}}{\mathrm{x}}+\mathrm{5}+\mathrm{6x} \\ $$$$\:\:\left(\mathrm{i}\right)×\mathrm{4}=\:\mathrm{4f}\left(\frac{\mathrm{1}}{\mathrm{x}}\right)+\mathrm{16f}\left(\mathrm{x}\right)=\mathrm{96x}+\mathrm{20}+\frac{\mathrm{24}}{\mathrm{x}} \\ $$$$\:\:\left(\mathrm{i}\right)−\left(\mathrm{ii}\right) \\ $$$$\:\:\:\Rightarrow\mathrm{15f}\left(\mathrm{x}\right)=\mathrm{90x}+\mathrm{15}…

U-n-is-a-sequence-wich-verify-n-N-U-n-U-n-1-1-n-1-calculate-U-n-interms-of-n-2-is-the-sequence-U-n-convergent-

Question Number 65488 by mathmax by abdo last updated on 30/Jul/19 $${U}_{{n}} {is}\:{a}\:{sequence}\:{wich}\:{verify}\:\:\forall{n}\in{N}^{\bigstar} \\ $$$${U}_{{n}} \:+{U}_{{n}+\mathrm{1}} =\frac{\mathrm{1}}{{n}} \\ $$$$\left.\mathrm{1}\right)\:{calculate}\:\:{U}_{{n}} \:{interms}\:{of}\:{n} \\ $$$$\left.\mathrm{2}\right)\:{is}\:{the}\:{sequence}\:{U}_{{n}} {convergent}? \\ $$…

U-n-is-a-sequence-wich-verify-U-n-U-n-1-1-n-2-1-find-U-n-interms-of-n-2-calculate-lim-n-U-n-

Question Number 65489 by mathmax by abdo last updated on 30/Jul/19 $${U}_{{n}} \:{is}\:{a}\:{sequence}\:{wich}\:{verify}\:\:{U}_{{n}} \:+{U}_{{n}+\mathrm{1}} =\frac{\mathrm{1}}{{n}^{\mathrm{2}} } \\ $$$$\left.\mathrm{1}\right)\:{find}\:{U}_{{n}} \:{interms}\:{of}\:{n} \\ $$$$\left.\mathrm{2}\right)\:{calculate}\:{lim}_{{n}\rightarrow+\infty} \:{U}_{{n}} \\ $$ Commented…