19.6.1.7 Lebesgue Measure and Integration

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