Metamath Proof Explorer


Theorem dvmulf

Description: The product rule for everywhere-differentiable functions. (Contributed by Mario Carneiro, 9-Aug-2014) (Revised by Mario Carneiro, 10-Feb-2015)

Ref Expression
Hypotheses dvaddf.s φ S
dvaddf.f φ F : X
dvaddf.g φ G : X
dvaddf.df φ dom F S = X
dvaddf.dg φ dom G S = X
Assertion dvmulf φ S D F × f G = F S × f G + f G S × f F

Proof

Step Hyp Ref Expression
1 dvaddf.s φ S
2 dvaddf.f φ F : X
3 dvaddf.g φ G : X
4 dvaddf.df φ dom F S = X
5 dvaddf.dg φ dom G S = X
6 2 adantr φ x X F : X
7 dvbsss dom F S S
8 4 7 eqsstrrdi φ X S
9 8 adantr φ x X X S
10 3 adantr φ x X G : X
11 1 adantr φ x X S
12 4 eleq2d φ x dom F S x X
13 12 biimpar φ x X x dom F S
14 5 eleq2d φ x dom G S x X
15 14 biimpar φ x X x dom G S
16 6 9 10 9 11 13 15 dvmul φ x X F × f G S x = F S x G x + G S x F x
17 16 mpteq2dva φ x X F × f G S x = x X F S x G x + G S x F x
18 dvfg S F × f G S : dom F × f G S
19 1 18 syl φ F × f G S : dom F × f G S
20 recnprss S S
21 1 20 syl φ S
22 mulcl x y x y
23 22 adantl φ x y x y
24 1 8 ssexd φ X V
25 inidm X X = X
26 23 2 3 24 24 25 off φ F × f G : X
27 21 26 8 dvbss φ dom F × f G S X
28 21 adantr φ x X S
29 dvfg S F S : dom F S
30 1 29 syl φ F S : dom F S
31 30 adantr φ x X F S : dom F S
32 ffun F S : dom F S Fun F S
33 funfvbrb Fun F S x dom F S x F S F S x
34 31 32 33 3syl φ x X x dom F S x F S F S x
35 13 34 mpbid φ x X x F S F S x
36 dvfg S G S : dom G S
37 1 36 syl φ G S : dom G S
38 37 adantr φ x X G S : dom G S
39 ffun G S : dom G S Fun G S
40 funfvbrb Fun G S x dom G S x G S G S x
41 38 39 40 3syl φ x X x dom G S x G S G S x
42 15 41 mpbid φ x X x G S G S x
43 eqid TopOpen fld = TopOpen fld
44 6 9 10 9 28 35 42 43 dvmulbr φ x X x F × f G S F S x G x + G S x F x
45 reldv Rel F × f G S
46 45 releldmi x F × f G S F S x G x + G S x F x x dom F × f G S
47 44 46 syl φ x X x dom F × f G S
48 27 47 eqelssd φ dom F × f G S = X
49 48 feq2d φ F × f G S : dom F × f G S F × f G S : X
50 19 49 mpbid φ F × f G S : X
51 50 feqmptd φ S D F × f G = x X F × f G S x
52 ovexd φ x X F S x G x V
53 ovexd φ x X G S x F x V
54 fvexd φ x X F S x V
55 fvexd φ x X G x V
56 4 feq2d φ F S : dom F S F S : X
57 30 56 mpbid φ F S : X
58 57 feqmptd φ S D F = x X F S x
59 3 feqmptd φ G = x X G x
60 24 54 55 58 59 offval2 φ F S × f G = x X F S x G x
61 fvexd φ x X G S x V
62 fvexd φ x X F x V
63 5 feq2d φ G S : dom G S G S : X
64 37 63 mpbid φ G S : X
65 64 feqmptd φ S D G = x X G S x
66 2 feqmptd φ F = x X F x
67 24 61 62 65 66 offval2 φ G S × f F = x X G S x F x
68 24 52 53 60 67 offval2 φ F S × f G + f G S × f F = x X F S x G x + G S x F x
69 17 51 68 3eqtr4d φ S D F × f G = F S × f G + f G S × f F