theorem :: INTEGR13:22
for A being non empty closed_interval Subset of REAL
for f being PartFunc of REAL,REAL
for Z being open Subset of REAL st A c= Z & f = - ((exp_R * cot) / (sin ^2)) & Z = dom f & f | A is continuous holds
integral (f,A) = ((exp_R * cot) . (upper_bound A)) - ((exp_R * cot) . (lower_bound A))