let A be closed-interval Subset of REAL; 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 * exp_R) holds
integral (f,A) = ((- (cos * exp_R)) . (upper_bound A)) - ((- (cos * exp_R)) . (lower_bound A))
let f be PartFunc of REAL,REAL; for Z being open Subset of REAL st A c= Z & Z = dom f & f = exp_R (#) (sin * exp_R) holds
integral (f,A) = ((- (cos * exp_R)) . (upper_bound A)) - ((- (cos * exp_R)) . (lower_bound A))
let Z be open Subset of REAL; ( A c= Z & Z = dom f & f = exp_R (#) (sin * exp_R) implies integral (f,A) = ((- (cos * exp_R)) . (upper_bound A)) - ((- (cos * exp_R)) . (lower_bound A)) )
assume A1:
( A c= Z & Z = dom f & f = exp_R (#) (sin * exp_R) )
; integral (f,A) = ((- (cos * exp_R)) . (upper_bound A)) - ((- (cos * exp_R)) . (lower_bound A))
then
Z = (dom exp_R) /\ (dom (sin * exp_R))
by VALUED_1:def 4;
then A2:
( Z c= dom exp_R & Z c= dom (sin * exp_R) )
by XBOOLE_1:18;
for y being set st y in Z holds
y in dom (cos * exp_R)
then A3:
Z c= dom (cos * exp_R)
by TARSKI:def 3;
A4:
sin * exp_R is_differentiable_on Z
by A2, FDIFF_7:34;
exp_R is_differentiable_on Z
by FDIFF_1:34, TAYLOR_1:16;
then
f | Z is continuous
by A1, A4, FDIFF_1:29, FDIFF_1:33;
then
f | A is continuous
by A1, FCONT_1:17;
then A5:
( f is_integrable_on A & f | A is bounded )
by A1, INTEGRA5:10, INTEGRA5:11;
A6:
cos * exp_R is_differentiable_on Z
by A3, FDIFF_7:35;
A7:
Z c= dom (- (cos * exp_R))
by A3, VALUED_1:8;
then A8:
(- 1) (#) (cos * exp_R) is_differentiable_on Z
by A6, Lm1, FDIFF_1:28;
A9:
for x being Real st x in Z holds
((- (cos * exp_R)) `| Z) . x = (exp_R . x) * (sin . (exp_R . x))
proof
let x be
Real;
( x in Z implies ((- (cos * exp_R)) `| Z) . x = (exp_R . x) * (sin . (exp_R . x)) )
assume A10:
x in Z
;
((- (cos * exp_R)) `| Z) . x = (exp_R . x) * (sin . (exp_R . x))
A11:
exp_R is_differentiable_in x
by SIN_COS:70;
A12:
cos is_differentiable_in exp_R . x
by SIN_COS:68;
A13:
cos * exp_R is_differentiable_in x
by A6, A10, FDIFF_1:16;
((- (cos * exp_R)) `| Z) . x =
diff (
(- (cos * exp_R)),
x)
by A8, A10, FDIFF_1:def 8
.=
(- 1) * (diff ((cos * exp_R),x))
by A13, Lm1, FDIFF_1:23
.=
(- 1) * ((diff (cos,(exp_R . x))) * (diff (exp_R,x)))
by A11, A12, FDIFF_2:13
.=
(- 1) * ((- (sin . (exp_R . x))) * (diff (exp_R,x)))
by SIN_COS:68
.=
(- 1) * ((- (sin . (exp_R . x))) * (exp_R . x))
by SIN_COS:70
.=
(exp_R . x) * (sin . (exp_R . x))
;
hence
((- (cos * exp_R)) `| Z) . x = (exp_R . x) * (sin . (exp_R . x))
;
verum
end;
A14:
for x being Real st x in Z holds
f . x = (exp_R . x) * (sin . (exp_R . x))
A16:
for x being Real st x in dom ((- (cos * exp_R)) `| Z) holds
((- (cos * exp_R)) `| Z) . x = f . x
dom ((- (cos * exp_R)) `| Z) = dom f
by A1, A8, FDIFF_1:def 8;
then
(- (cos * exp_R)) `| Z = f
by A16, PARTFUN1:34;
hence
integral (f,A) = ((- (cos * exp_R)) . (upper_bound A)) - ((- (cos * exp_R)) . (lower_bound A))
by A1, A5, A6, A7, Lm1, FDIFF_1:28, INTEGRA5:13; verum