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Category: Relation and Functions

let-a-n-k-2-n-cos-pi-2-k-prove-that-a-n-ks-decreasing-2-let-b-n-a-n-cos-pi-2-n-find-lim-n-a-n-b-n-

Question Number 30488 by abdo imad last updated on 22/Feb/18 $${let}\:\:\:{a}_{{n}} =\:\prod_{{k}=\mathrm{2}} ^{{n}} \:{cos}\left(\frac{\pi}{\mathrm{2}^{{k}} }\right)\:.{prove}\:{that}\:\left({a}_{{n}} \right)\:{ks}\:{decreasing}. \\ $$$$\left.\mathrm{2}\right)\:{let}\:{b}_{{n}} ={a}_{{n}} {cos}\left(\frac{\pi}{\mathrm{2}^{{n}} }\right)\:\:{find}\:{lim}_{{n}\rightarrow\infty} \left({a}_{{n}} \:−{b}_{{n}} \right). \\…

let-give-a-n-k-1-n-cos-pi-k-2-and-b-n-k-1-n-sin-pi-k-2-1-find-a-equivalent-foe-a-n-and-b-n-2-find-a-equivalent-of-a-n-b-n-

Question Number 30486 by abdo imad last updated on 22/Feb/18 $${let}\:{give}\:{a}_{{n}} =\:\prod_{{k}=\mathrm{1}} ^{{n}} \:{cos}\left(\:\frac{\pi}{\left({k}+\mathrm{2}\right)!}\right)\:{and} \\ $$$${b}_{{n}} =\prod_{{k}=\mathrm{1}} ^{{n}} \:\:{sin}\left(\frac{\pi}{\left({k}+\mathrm{2}\right)!}\right) \\ $$$$\left.\mathrm{1}\right)\:{find}\:{a}\:{equivalent}\:{foe}\:{a}_{{n}} \:{and}\:{b}_{{n}} \\ $$$$\left.\mathrm{2}\right)\:{find}\:{a}\:{equivalent}\:{of}\:{a}_{{n}} .{b}_{{n}}…

1-prove-that-x-gt-0-x-x-1-ln-1-x-x-2-let-put-S-n-k-1-n-1-k-n-find-lim-n-S-n-

Question Number 30485 by abdo imad last updated on 22/Feb/18 $$\left.\mathrm{1}\right)\:{prove}\:{that}\:\forall\:{x}>\mathrm{0}\:\:\:\frac{{x}}{{x}+\mathrm{1}}\:\leqslant\:{ln}\left(\mathrm{1}+{x}\right)\leqslant{x} \\ $$$$\left.\mathrm{2}\right)\:{let}\:{put}\:\:{S}_{{n}} =\:\prod_{{k}=\mathrm{1}} ^{{n}} \left(\mathrm{1}\:+\:\frac{{k}}{{n}}\right)\:{find}\:{lim}_{{n}\rightarrow\infty} \:{S}_{{n}} \:\:. \\ $$ Commented by chantriachheang last updated…

1-prove-that-if-f-is-decreasing-function-we-have-n-n-1-f-t-dt-lt-f-n-lt-n-1-n-f-t-dt-2-let-put-S-n-k-1-n-2-1-2-k-calculate-S-n-

Question Number 30484 by abdo imad last updated on 22/Feb/18 $$\left.\mathrm{1}\right)\:{prove}\:{that}\:{if}\:{f}\:{is}\:{decreasing}\:{function}\:{we}\:{have} \\ $$$$\:\int_{{n}} ^{{n}+\mathrm{1}} {f}\left({t}\right){dt}\:<{f}\left({n}\right)<\:\int_{{n}−\mathrm{1}} ^{{n}} \:{f}\left({t}\right)\:{dt}\:\:. \\ $$$$\left.\mathrm{2}\right)\:{let}\:{put}\:\:{S}_{{n}} =\:\sum_{{k}=\mathrm{1}} ^{{n}^{\mathrm{2}} } \:\:\:\frac{\mathrm{1}}{\mathrm{2}\sqrt{{k}}}\:.{calculate}\:\left[{S}_{{n}} \right]. \\…

we-define-the-bernoulli-polynomial-B-n-by-b-0-1-and-n-N-b-n-n-b-n-1-and-0-1-b-n-t-dt-0-1-find-b-n-1-b-n-0-for-n-2-2-prove-that-b-n-x-1-n-b-n-1-x-n-N-3-calculate-b-0

Question Number 30483 by abdo imad last updated on 22/Feb/18 $${we}\:{define}\:{the}\:{bernoulli}\:{polynomial}\:{B}_{{n}} \:{by} \\ $$$${b}_{\mathrm{0}} =\mathrm{1}\:{and}\:\forall{n}\in\:{N}^{\bigstar} \:\:\:{b}_{{n}} ^{'} ={n}\:{b}_{{n}−\mathrm{1}} \:\:{and}\:\:\int_{\mathrm{0}} ^{\mathrm{1}} {b}_{{n}} \left({t}\right){dt}=\mathrm{0} \\ $$$$\left.\mathrm{1}\right)\:{find}\:{b}_{{n}} \left(\mathrm{1}\right)−{b}_{{n}}…