let r be Element of REAL ; :: thesis: 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 ))]|

let f1, f2, f3, g1, g2, g3 be PartFunc of REAL ,REAL ; :: thesis: 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 ))]|

let t0 be Real; :: thesis: ( 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 implies 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 ))]| )
assume that
A1: ( f1 is_differentiable_in t0 & f2 is_differentiable_in t0 & f3 is_differentiable_in t0 ) and
A2: ( g1 is_differentiable_in t0 & g2 is_differentiable_in t0 & g3 is_differentiable_in t0 ) and
A3: ( g1 . t0 <> 0 & g2 . t0 <> 0 & g3 . t0 <> 0 ) ; :: thesis: 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 ))]|
A4: ( r (#) f1 is_differentiable_in t0 & r (#) f2 is_differentiable_in t0 & r (#) f3 is_differentiable_in t0 ) by A1, FDIFF_1:23;
then VFuncdiff ((r (#) f1) / g1),((r (#) f2) / g2),((r (#) f3) / g3),t0 = |[((((diff (r (#) f1),t0) * (g1 . t0)) - ((diff g1,t0) * ((r (#) f1) . t0))) / ((g1 . t0) ^2 )),(diff ((r (#) f2) / g2),t0),(diff ((r (#) f3) / g3),t0)]| by A2, A3, FDIFF_2:14
.= |[((((diff (r (#) f1),t0) * (g1 . t0)) - ((diff g1,t0) * ((r (#) f1) . t0))) / ((g1 . t0) ^2 )),((((diff (r (#) f2),t0) * (g2 . t0)) - ((diff g2,t0) * ((r (#) f2) . t0))) / ((g2 . t0) ^2 )),(diff ((r (#) f3) / g3),t0)]| by A2, A3, A4, FDIFF_2:14
.= |[((((diff (r (#) f1),t0) * (g1 . t0)) - ((diff g1,t0) * ((r (#) f1) . t0))) / ((g1 . t0) ^2 )),((((diff (r (#) f2),t0) * (g2 . t0)) - ((diff g2,t0) * ((r (#) f2) . t0))) / ((g2 . t0) ^2 )),((((diff (r (#) f3),t0) * (g3 . t0)) - ((diff g3,t0) * ((r (#) f3) . t0))) / ((g3 . t0) ^2 ))]| by A2, A3, A4, FDIFF_2:14
.= |[((((r * (diff f1,t0)) * (g1 . t0)) - ((diff g1,t0) * ((r (#) f1) . t0))) / ((g1 . t0) ^2 )),((((diff (r (#) f2),t0) * (g2 . t0)) - ((diff g2,t0) * ((r (#) f2) . t0))) / ((g2 . t0) ^2 )),((((diff (r (#) f3),t0) * (g3 . t0)) - ((diff g3,t0) * ((r (#) f3) . t0))) / ((g3 . t0) ^2 ))]| by A1, FDIFF_1:23
.= |[((((r * (diff f1,t0)) * (g1 . t0)) - ((diff g1,t0) * ((r (#) f1) . t0))) / ((g1 . t0) ^2 )),((((r * (diff f2,t0)) * (g2 . t0)) - ((diff g2,t0) * ((r (#) f2) . t0))) / ((g2 . t0) ^2 )),((((diff (r (#) f3),t0) * (g3 . t0)) - ((diff g3,t0) * ((r (#) f3) . t0))) / ((g3 . t0) ^2 ))]| by A1, FDIFF_1:23
.= |[((((r * (diff f1,t0)) * (g1 . t0)) - ((diff g1,t0) * ((r (#) f1) . t0))) / ((g1 . t0) ^2 )),((((r * (diff f2,t0)) * (g2 . t0)) - ((diff g2,t0) * ((r (#) f2) . t0))) / ((g2 . t0) ^2 )),((((r * (diff f3,t0)) * (g3 . t0)) - ((diff g3,t0) * ((r (#) f3) . t0))) / ((g3 . t0) ^2 ))]| by A1, FDIFF_1:23
.= |[((((r * (diff f1,t0)) * (g1 . t0)) - ((diff g1,t0) * (r * (f1 . t0)))) / ((g1 . t0) ^2 )),((((r * (diff f2,t0)) * (g2 . t0)) - ((diff g2,t0) * ((r (#) f2) . t0))) / ((g2 . t0) ^2 )),((((r * (diff f3,t0)) * (g3 . t0)) - ((diff g3,t0) * ((r (#) f3) . t0))) / ((g3 . t0) ^2 ))]| by VALUED_1:6
.= |[((((r * (diff f1,t0)) * (g1 . t0)) - ((diff g1,t0) * (r * (f1 . t0)))) / ((g1 . t0) ^2 )),((((r * (diff f2,t0)) * (g2 . t0)) - ((diff g2,t0) * (r * (f2 . t0)))) / ((g2 . t0) ^2 )),((((r * (diff f3,t0)) * (g3 . t0)) - ((diff g3,t0) * ((r (#) f3) . t0))) / ((g3 . t0) ^2 ))]| by VALUED_1:6
.= |[((((r * (diff f1,t0)) * (g1 . t0)) - ((diff g1,t0) * (r * (f1 . t0)))) / ((g1 . t0) ^2 )),((((r * (diff f2,t0)) * (g2 . t0)) - ((diff g2,t0) * (r * (f2 . t0)))) / ((g2 . t0) ^2 )),((((r * (diff f3,t0)) * (g3 . t0)) - ((diff g3,t0) * (r * (f3 . t0)))) / ((g3 . t0) ^2 ))]| by VALUED_1:6
.= |[((r * (((diff f1,t0) * (g1 . t0)) - ((diff g1,t0) * (f1 . t0)))) / ((g1 . t0) ^2 )),((r * (((diff f2,t0) * (g2 . t0)) - ((diff g2,t0) * (f2 . t0)))) / ((g2 . t0) ^2 )),((r * (((diff f3,t0) * (g3 . t0)) - ((diff g3,t0) * (f3 . t0)))) / ((g3 . t0) ^2 ))]|
.= |[(r * ((((diff f1,t0) * (g1 . t0)) - ((diff g1,t0) * (f1 . t0))) / ((g1 . t0) ^2 ))),((r * (((diff f2,t0) * (g2 . t0)) - ((diff g2,t0) * (f2 . t0)))) / ((g2 . t0) ^2 )),((r * (((diff f3,t0) * (g3 . t0)) - ((diff g3,t0) * (f3 . t0)))) / ((g3 . t0) ^2 ))]| by XCMPLX_1:75
.= |[(r * ((((diff f1,t0) * (g1 . t0)) - ((diff g1,t0) * (f1 . t0))) / ((g1 . t0) ^2 ))),(r * ((((diff f2,t0) * (g2 . t0)) - ((diff g2,t0) * (f2 . t0))) / ((g2 . t0) ^2 ))),((r * (((diff f3,t0) * (g3 . t0)) - ((diff g3,t0) * (f3 . t0)))) / ((g3 . t0) ^2 ))]| by XCMPLX_1:75
.= |[(r * ((((diff f1,t0) * (g1 . t0)) - ((diff g1,t0) * (f1 . t0))) / ((g1 . t0) ^2 ))),(r * ((((diff f2,t0) * (g2 . t0)) - ((diff g2,t0) * (f2 . t0))) / ((g2 . t0) ^2 ))),(r * ((((diff f3,t0) * (g3 . t0)) - ((diff g3,t0) * (f3 . t0))) / ((g3 . t0) ^2 )))]| by XCMPLX_1:75
.= 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 ))]| by LmA8 ;
hence 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 ))]| ; :: thesis: verum