theorem Th22: :: FUZZY_9:29

for a, b, c, d being Real st a < b & b < c & c < d holds
for x being object st x in [.c,d.] holds
(TrapezoidalFS (a,b,c,d)) . x = (AffineMap ((- (1 / (d - c))),(d / (d - c)))) . x