theorem Th17:
for
A being non
empty closed_interval Subset of
REAL for
a,
b,
p,
q being
Real for
f being
Function of
REAL,
REAL st
a <> p &
f = ((AffineMap (a,b)) | ].-infty,((q - b) / (a - p)).[) +* ((AffineMap (p,q)) | [.((q - b) / (a - p)),+infty.[) holds
( (
(q - b) / (a - p) in A implies
integral (
f,
A)
= (integral ((AffineMap (a,b)),['(lower_bound A),((q - b) / (a - p))'])) + (integral ((AffineMap (p,q)),['((q - b) / (a - p)),(upper_bound A)'])) ) & (
(q - b) / (a - p) <= lower_bound A implies
integral (
f,
A)
= integral (
(AffineMap (p,q)),
A) ) & (
(q - b) / (a - p) >= upper_bound A implies
integral (
f,
A)
= integral (
(AffineMap (a,b)),
A) ) )