Question Number 131874 by mnjuly1970 last updated on 09/Feb/21
![... calculus ... φ =∫_0 ^( ∞) ((tanh^2 (x)dx)/x^2 ) =?](https://www.tinkutara.com/question/Q131874.png)
$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:…\:{calculus}\:… \\ $$$$\:\:\:\phi\:=\int_{\mathrm{0}} ^{\:\infty} \frac{{tanh}^{\mathrm{2}} \left({x}\right){dx}}{{x}^{\mathrm{2}} }\:=? \\ $$$$ \\ $$