theorem :: EUCLID_8:109

for r being Real
for f1, f2, f3, g1, g2, g3 being PartFunc of REAL,REAL
for t0 being Real st f1 is_differentiable_in t0 & f2 is_differentiable_in t0 & f3 is_differentiable_in t0 & g1 is_differentiable_in t0 & g2 is_differentiable_in t0 & g3 is_differentiable_in t0 & g1 . t0 <> 0 & g2 . t0 <> 0 & g3 . t0 <> 0 holds
VFuncdiff (((r (#) f1) / g1),((r (#) f2) / g2),((r (#) f3) / g3),t0) = r * |[((((diff (f1,t0)) * (g1 . t0)) - ((diff (g1,t0)) * (f1 . t0))) / ((g1 . t0) ^2)),((((diff (f2,t0)) * (g2 . t0)) - ((diff (g2,t0)) * (f2 . t0))) / ((g2 . t0) ^2)),((((diff (f3,t0)) * (g3 . t0)) - ((diff (g3,t0)) * (f3 . t0))) / ((g3 . t0) ^2))]|