Monday, August 24, 2015

calculus - Is there an integral for $frac{1}{zeta(3)} $?

There are many integral representations for $\zeta(3)$



Some lesser known are for instance :



$$\int_0^1\frac{x(1-x)}{\sin\pi x}\text{d}x= 7\frac{\zeta(3)}{\pi^3} $$



$$\int_0^1 \frac{\operatorname{li}(x)^3 \space (x-1)}{x^3} \text{d}x = \frac{\zeta(3)}{4} $$



$$\int_0^\pi x(\pi - x) \csc(x) \space \text{d}x = 7 \space \zeta(3) $$




$$ \int_0^{\infty} \frac{\tanh^2(x)}{x^2} \text{d}x = \frac{ 14 \space \zeta(3)}{\pi^2} $$



$$\int_0^{\frac{\pi}{2}} x \log\tan x \;\text{d}x=\frac{7}{8}\zeta(3)$$



$\zeta(2) $ also has many integral representations as does $ \frac{1}{\zeta(2)} $ , although this probability is because $\frac{1}{\pi}$ and $\frac{1}{\pi^2} $ have many.
Well I suspect that because I know no simple integral expression for $\frac{1}{\zeta(3)} $.



My question is: is there some interesting integral $^*$ whose result is simply $\frac{1}{\zeta(3)}$?




Note



$^*$ Interesting integral means that things like



$$\int\limits_0^{+\infty} e^{- \zeta(3) \space x}\ \text{d}x = \frac{1}{\zeta(3)} $$



are not a good answer to my question.

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