let A be non empty closed_interval Subset of REAL; :: thesis: for f being PartFunc of REAL,REAL
for Z being open Subset of REAL st A c= Z & Z = dom f & f = (exp_R (#) (sin / cos)) + (exp_R / (cos ^2)) holds
integral (f,A) = ((exp_R (#) tan) . (upper_bound A)) - ((exp_R (#) tan) . (lower_bound A))
let f be PartFunc of REAL,REAL; :: thesis: for Z being open Subset of REAL st A c= Z & Z = dom f & f = (exp_R (#) (sin / cos)) + (exp_R / (cos ^2)) holds
integral (f,A) = ((exp_R (#) tan) . (upper_bound A)) - ((exp_R (#) tan) . (lower_bound A))
let Z be open Subset of REAL; :: thesis: ( A c= Z & Z = dom f & f = (exp_R (#) (sin / cos)) + (exp_R / (cos ^2)) implies integral (f,A) = ((exp_R (#) tan) . (upper_bound A)) - ((exp_R (#) tan) . (lower_bound A)) )
assume A1: ( A c= Z & Z = dom f & f = (exp_R (#) (sin / cos)) + (exp_R / (cos ^2)) ) ; :: thesis: integral (f,A) = ((exp_R (#) tan) . (upper_bound A)) - ((exp_R (#) tan) . (lower_bound A))
then Z = (dom (exp_R (#) (sin / cos))) /\ (dom (exp_R / (cos ^2))) by VALUED_1:def 1;
then A2: ( Z c= dom (exp_R (#) (sin / cos)) & Z c= dom (exp_R / (cos ^2)) ) by XBOOLE_1:18;
A3: dom (exp_R (#) (sin / cos)) c= (dom exp_R) /\ (dom (sin / cos)) by VALUED_1:def 4;
dom (exp_R / (cos ^2)) c= (dom exp_R) /\ ((dom (cos ^2)) \ ((cos ^2) " {0})) by RFUNCT_1:def 1;
then ( dom (exp_R (#) (sin / cos)) c= dom exp_R & dom (exp_R (#) (sin / cos)) c= dom (sin / cos) & dom (exp_R / (cos ^2)) c= (dom (cos ^2)) \ ((cos ^2) " {0}) ) by A3, XBOOLE_1:18;
then A4: ( Z c= dom exp_R & Z c= dom (sin / cos) & Z c= (dom (cos ^2)) \ ((cos ^2) " {0}) ) by A2;
A5: exp_R is_differentiable_on Z by FDIFF_1:26, TAYLOR_1:16;
for x being Real st x in Z holds
sin / cos is_differentiable_in x

proof

let x be Real; :: thesis: ( x in Z implies sin / cos is_differentiable_in x )
assume x in Z ; :: thesis: sin / cos is_differentiable_in x
then cos . x <> 0 by A4, FDIFF_8:1;
hence sin / cos is_differentiable_in x by FDIFF_7:46; :: thesis: verum

end;

then sin / cos is_differentiable_on Z by A4, FDIFF_1:9;
then A6: exp_R (#) (sin / cos) is_differentiable_on Z by A2, A5, FDIFF_1:21;
cos is_differentiable_on Z by FDIFF_1:26, SIN_COS:67;
then A7: cos ^2 is_differentiable_on Z by FDIFF_2:20;
for x being Real st x in Z holds
(cos ^2) . x <> 0

proof

let x be Real; :: thesis: ( x in Z implies (cos ^2) . x <> 0 )
assume x in Z ; :: thesis: (cos ^2) . x <> 0
then x in dom (exp_R / (cos ^2)) by A2;
then x in (dom exp_R) /\ ((dom (cos ^2)) \ ((cos ^2) " {0})) by RFUNCT_1:def 1;
then x in (dom (cos ^2)) \ ((cos ^2) " {0}) by XBOOLE_0:def 4;
then x in dom ((cos ^2) ^) by RFUNCT_1:def 2;
hence (cos ^2) . x <> 0 by RFUNCT_1:3; :: thesis: verum

end;

then exp_R / (cos ^2) is_differentiable_on Z by A5, A7, FDIFF_2:21;
then f | Z is continuous by A1, A6, FDIFF_1:18, FDIFF_1:25;
then f | A is continuous by A1, FCONT_1:16;
then A8: ( f is_integrable_on A & f | A is bounded ) by A1, INTEGRA5:10, INTEGRA5:11;
A9: exp_R (#) tan is_differentiable_on Z by A2, FDIFF_8:30;
A10: for x being Real st x in Z holds
f . x = (((exp_R . x) * (sin . x)) / (cos . x)) + ((exp_R . x) / ((cos . x) ^2))

proof

let x be Real; :: thesis: ( x in Z implies f . x = (((exp_R . x) * (sin . x)) / (cos . x)) + ((exp_R . x) / ((cos . x) ^2)) )
assume A11: x in Z ; :: thesis: f . x = (((exp_R . x) * (sin . x)) / (cos . x)) + ((exp_R . x) / ((cos . x) ^2))
then ((exp_R (#) (sin / cos)) + (exp_R / (cos ^2))) . x = ((exp_R (#) (sin / cos)) . x) + ((exp_R / (cos ^2)) . x) by A1, VALUED_1:def 1
.= ((exp_R . x) * ((sin / cos) . x)) + ((exp_R / (cos ^2)) . x) by VALUED_1:5
.= ((exp_R . x) * ((sin . x) * ((cos . x) "))) + ((exp_R / (cos ^2)) . x) by A4, A11, RFUNCT_1:def 1
.= (((exp_R . x) * (sin . x)) / (cos . x)) + ((exp_R . x) / ((cos ^2) . x)) by A2, A11, RFUNCT_1:def 1
.= (((exp_R . x) * (sin . x)) / (cos . x)) + ((exp_R . x) / ((cos . x) ^2)) by VALUED_1:11 ;
hence f . x = (((exp_R . x) * (sin . x)) / (cos . x)) + ((exp_R . x) / ((cos . x) ^2)) by A1; :: thesis: verum

end;

A12: for x being Element of REAL st x in dom ((exp_R (#) tan) `| Z) holds
((exp_R (#) tan) `| Z) . x = f . x

proof

let x be Element of REAL ; :: thesis: ( x in dom ((exp_R (#) tan) `| Z) implies ((exp_R (#) tan) `| Z) . x = f . x )
assume x in dom ((exp_R (#) tan) `| Z) ; :: thesis: ((exp_R (#) tan) `| Z) . x = f . x
then A13: x in Z by A9, FDIFF_1:def 7;
then ((exp_R (#) tan) `| Z) . x = (((exp_R . x) * (sin . x)) / (cos . x)) + ((exp_R . x) / ((cos . x) ^2)) by A2, FDIFF_8:30
.= f . x by A13, A10 ;
hence ((exp_R (#) tan) `| Z) . x = f . x ; :: thesis: verum

end;

dom ((exp_R (#) tan) `| Z) = dom f by A1, A9, FDIFF_1:def 7;
then (exp_R (#) tan) `| Z = f by A12, PARTFUN1:5;
hence integral (f,A) = ((exp_R (#) tan) . (upper_bound A)) - ((exp_R (#) tan) . (lower_bound A)) by A1, A8, A2, FDIFF_8:30, INTEGRA5:13; :: thesis: verum