$\huge \int 5\tanh\!\left(x\right)\mathop{\rm sech}\nolimits^{2}\!\left(x\right) \, dx $ $\huge \begin{align} \let u &= \tanh(x) \\ \let \d u &= \op{sech}^2x \\ \\ \int 5\tanh\!\left(x\right)\mathop{\rm sech}\nolimits^{2}\!\left(x\right) \, dx &= 5\int u\d u \\ &= \frac{5}{2}u^2 +C\\ &= \frac{5}{2} \tanh^2 x+C \end{align} $