Editing Improper integral (section)

===Improper integrals with singularities===
If ''f'' is a non-negative function which is unbounded in a domain ''A'', then the improper integral of ''f'' is defined by truncating ''f'' at some cutoff ''M'', integrating the resulting function, and then taking the limit as ''M'' tends to infinity.  That is for <math>M>0</math>, set <math>f_M=\min\{f,M\}</math>.  Then define
:<math>\int_A f = \lim_{M\to\infty}\int_A f_M</math>
provided this limit exists.