Metamath Proof Explorer


Theorem dvmptmul

Description: Function-builder for derivative, product rule. (Contributed by Mario Carneiro, 1-Sep-2014) (Revised by Mario Carneiro, 11-Feb-2015)

Ref Expression
Hypotheses dvmptadd.s φ S
dvmptadd.a φ x X A
dvmptadd.b φ x X B V
dvmptadd.da φ dx X A dS x = x X B
dvmptadd.c φ x X C
dvmptadd.d φ x X D W
dvmptadd.dc φ dx X C dS x = x X D
Assertion dvmptmul φ dx X A C dS x = x X B C + D A

Proof

Step Hyp Ref Expression
1 dvmptadd.s φ S
2 dvmptadd.a φ x X A
3 dvmptadd.b φ x X B V
4 dvmptadd.da φ dx X A dS x = x X B
5 dvmptadd.c φ x X C
6 dvmptadd.d φ x X D W
7 dvmptadd.dc φ dx X C dS x = x X D
8 2 fmpttd φ x X A : X
9 5 fmpttd φ x X C : X
10 4 dmeqd φ dom dx X A dS x = dom x X B
11 3 ralrimiva φ x X B V
12 dmmptg x X B V dom x X B = X
13 11 12 syl φ dom x X B = X
14 10 13 eqtrd φ dom dx X A dS x = X
15 7 dmeqd φ dom dx X C dS x = dom x X D
16 6 ralrimiva φ x X D W
17 dmmptg x X D W dom x X D = X
18 16 17 syl φ dom x X D = X
19 15 18 eqtrd φ dom dx X C dS x = X
20 1 8 9 14 19 dvmulf φ S D x X A × f x X C = dx X A dS x × f x X C + f dx X C dS x × f x X A
21 ovex dx X C dS x V
22 21 dmex dom dx X C dS x V
23 19 22 eqeltrrdi φ X V
24 eqidd φ x X A = x X A
25 eqidd φ x X C = x X C
26 23 2 5 24 25 offval2 φ x X A × f x X C = x X A C
27 26 oveq2d φ S D x X A × f x X C = dx X A C dS x
28 ovexd φ x X B C V
29 ovexd φ x X D A V
30 23 3 5 4 25 offval2 φ dx X A dS x × f x X C = x X B C
31 23 6 2 7 24 offval2 φ dx X C dS x × f x X A = x X D A
32 23 28 29 30 31 offval2 φ dx X A dS x × f x X C + f dx X C dS x × f x X A = x X B C + D A
33 20 27 32 3eqtr3d φ dx X A C dS x = x X B C + D A