19.6.1.8 Lebesgue Measure and Integration

Condition: Find the integral of the Lebag \ [\ Begin {Array} {l} \ int _ {[0; \ infty)} F D \ MU \ Text {from function} f (x) = \ frac {1} {n^{2} (n+1)}, \\ \ text {if} x \ in [(n-1) n; n (n+1)), n \ in \ mathbb {n}. \ end {Array} \]