Solution (source code)

= Solution

The <monotone convergence theorem> states that if $f_n$ are nonnegative <measurable function>[measurable functions] on a <measure space> and $f_n\uparrow f$ almost everywhere, then
$$
\boxed{\int f\,d\mu=\lim_{n\to\infty}\int f_n\,d\mu.}
$$
Either side is allowed to be $+\infty$; no integrable dominating function is required.