theorem Th22: :: DIFF_1:22

for n being Nat
for h, x being Real
for f1, f2 being Function of REAL,REAL holds ((cdif ((f1 + f2),h)) . (n + 1)) . x = (((cdif (f1,h)) . (n + 1)) . x) + (((cdif (f2,h)) . (n + 1)) . x)