19.6.1.7 Lebesgue measure and integration

\( \underline{\text { Condition: }} \) Is the function \( f \) integrable on the set \( (0 ; 1] ? \) \[ f(x)=(-1)^{n}(n+1), \text { if } x \in\left(\frac{1}{n+1} ; \frac{1}{n}\right] . \]