Timeline for Show that $(\sum_{k=1}^{n}x_{k}\cos{k})^2+(\sum_{k=1}^{n}x_{k}\sin{k})^2\le (2+\frac{n}{4})\sum_{k=1}^{n}x^2_{k}$
Current License: CC BY-SA 4.0
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| when toggle format | what | by | license | comment | |
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| Mar 7, 2020 at 17:59 | comment | added | Vladimir Dotsenko | The condition $x_i>0$ is important, and you seem to have ignored it. If one allows all possible $x_i$, it is easy to get to values approximately $n/2$. | |
| Mar 7, 2020 at 17:48 | history | answered | Bazin | CC BY-SA 4.0 |