Neka je
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funkcija definirana s
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. Izračunaj
Let

be a function defined by

. Calculate the value of
[lang=hr]
Neka je $f: \mathbb{R} \rightarrow \mathbb{R}$ funkcija definirana s $f(x)=10^{2x}+10^x+1$. Izračunaj \[\sum_{x=1}^{2021} (x-1)f(\log_{10} x).\]
[/lang]
[lang=en]
Let $f: \mathbb{R} \rightarrow \mathbb{R}$ be a function defined by $f(x)=10^{2x}+10^x+1$. Calculate the value of \[\sum_{x=1}^{2021} (x-1)f(\log_{10} x).\]
[/lang]