theorem Th14: :: FDIFF_2:14

for x0 being Real
for f1, f2 being PartFunc of REAL,REAL st f2 . x0 <> 0 & f1 is_differentiable_in x0 & f2 is_differentiable_in x0 holds
( f1 / f2 is_differentiable_in x0 & diff ((f1 / f2),x0) = (((diff (f1,x0)) * (f2 . x0)) - ((diff (f2,x0)) * (f1 . x0))) / ((f2 . x0) ^2) )