Metamath Proof Explorer


Theorem expgrowthi

Description: Exponential growth and decay model. See expgrowth for more information. (Contributed by Steve Rodriguez, 4-Nov-2015)

Ref Expression
Hypotheses expgrowthi.s φS
expgrowthi.k φK
expgrowthi.y0 φC
expgrowthi.yt Y=tSCeKt
Assertion expgrowthi φSDY=S×K×fY

Proof

Step Hyp Ref Expression
1 expgrowthi.s φS
2 expgrowthi.k φK
3 expgrowthi.y0 φC
4 expgrowthi.yt Y=tSCeKt
5 oveq2 t=yKt=Ky
6 5 fveq2d t=yeKt=eKy
7 6 oveq2d t=yCeKt=CeKy
8 7 cbvmptv tSCeKt=ySCeKy
9 4 8 eqtri Y=ySCeKy
10 9 oveq2i SDY=dySCeKydSy
11 elpri SS=S=
12 eleq2 S=ySy
13 recn yy
14 12 13 syl6bi S=ySy
15 eleq2 S=ySy
16 15 biimpd S=ySy
17 14 16 jaoi S=S=ySy
18 1 11 17 3syl φySy
19 18 imp φySy
20 mulcl KyKy
21 2 20 sylan φyKy
22 efcl KyeKy
23 21 22 syl φyeKy
24 19 23 syldan φySeKy
25 ovexd φySKeKyV
26 cnelprrecn
27 26 a1i φ
28 19 21 syldan φySKy
29 2 adantr φySK
30 efcl xex
31 30 adantl φxex
32 1cnd φyS1
33 1 dvmptid φdySydSy=yS1
34 1 19 32 33 2 dvmptcmul φdySKydSy=ySK1
35 2 mulridd φK1=K
36 35 mpteq2dv φySK1=ySK
37 34 36 eqtrd φdySKydSy=ySK
38 dvef Dexp=exp
39 eff exp:
40 ffn exp:expFn
41 39 40 ax-mp expFn
42 dffn5 expFnexp=xex
43 41 42 mpbi exp=xex
44 43 oveq2i Dexp=dxexdx
45 38 44 43 3eqtr3i dxexdx=xex
46 45 a1i φdxexdx=xex
47 fveq2 x=Kyex=eKy
48 1 27 28 29 31 31 37 46 47 47 dvmptco φdySeKydSy=ySeKyK
49 mulcom eKyKeKyK=KeKy
50 24 2 49 syl2anr φφySeKyK=KeKy
51 50 anabss5 φySeKyK=KeKy
52 51 mpteq2dva φySeKyK=ySKeKy
53 48 52 eqtrd φdySeKydSy=ySKeKy
54 1 24 25 53 3 dvmptcmul φdySCeKydSy=ySCKeKy
55 3 2 24 3anim123i φφφySCKeKy
56 55 3anidm12 φφySCKeKy
57 56 anabss5 φySCKeKy
58 mul12 CKeKyCKeKy=KCeKy
59 57 58 syl φySCKeKy=KCeKy
60 59 mpteq2dva φySCKeKy=ySKCeKy
61 54 60 eqtrd φdySCeKydSy=ySKCeKy
62 10 61 eqtrid φSDY=ySKCeKy
63 ovexd φySCeKyV
64 fconstmpt S×K=ySK
65 64 a1i φS×K=ySK
66 9 a1i φY=ySCeKy
67 1 29 63 65 66 offval2 φS×K×fY=ySKCeKy
68 62 67 eqtr4d φSDY=S×K×fY