Matematické Fórum

byk7 · 03. 10. 2013 23:30

How many times does the function
$f(x):=\prod_{n=1}^{2013}\cos$\frac{x}{n}$$
change its sign on the interval $\left\langle 0,2013\pi/2\right\rangle$ ?

Note: I was inspired by Final round of Russian MO from 2009.
I didn't solve the problem (and I probably won't),
I just want to share this interesting task (from my point of view).

Matematické Fórum

#1 03. 10. 2013 23:30

Changing sign of product of cosines

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