Metamath Proof Explorer


Theorem binomcxplemcvg

Description: Lemma for binomcxp . The sum in binomcxplemnn0 and its derivative (see the next theorem, binomcxplemdvsum ) converge, as long as their base J is within the disk of convergence. Part of remark "This convergence allows us to apply term-by-term differentiation..." in the Wikibooks proof. (Contributed by Steve Rodriguez, 22-Apr-2020)

Ref Expression
Hypotheses binomcxp.a ( 𝜑𝐴 ∈ ℝ+ )
binomcxp.b ( 𝜑𝐵 ∈ ℝ )
binomcxp.lt ( 𝜑 → ( abs ‘ 𝐵 ) < ( abs ‘ 𝐴 ) )
binomcxp.c ( 𝜑𝐶 ∈ ℂ )
binomcxplem.f 𝐹 = ( 𝑗 ∈ ℕ0 ↦ ( 𝐶 C𝑐 𝑗 ) )
binomcxplem.s 𝑆 = ( 𝑏 ∈ ℂ ↦ ( 𝑘 ∈ ℕ0 ↦ ( ( 𝐹𝑘 ) · ( 𝑏𝑘 ) ) ) )
binomcxplem.r 𝑅 = sup ( { 𝑟 ∈ ℝ ∣ seq 0 ( + , ( 𝑆𝑟 ) ) ∈ dom ⇝ } , ℝ* , < )
binomcxplem.e 𝐸 = ( 𝑏 ∈ ℂ ↦ ( 𝑘 ∈ ℕ ↦ ( ( 𝑘 · ( 𝐹𝑘 ) ) · ( 𝑏 ↑ ( 𝑘 − 1 ) ) ) ) )
binomcxplem.d 𝐷 = ( abs “ ( 0 [,) 𝑅 ) )
Assertion binomcxplemcvg ( ( 𝜑𝐽𝐷 ) → ( seq 0 ( + , ( 𝑆𝐽 ) ) ∈ dom ⇝ ∧ seq 1 ( + , ( 𝐸𝐽 ) ) ∈ dom ⇝ ) )

Proof

Step Hyp Ref Expression
1 binomcxp.a ( 𝜑𝐴 ∈ ℝ+ )
2 binomcxp.b ( 𝜑𝐵 ∈ ℝ )
3 binomcxp.lt ( 𝜑 → ( abs ‘ 𝐵 ) < ( abs ‘ 𝐴 ) )
4 binomcxp.c ( 𝜑𝐶 ∈ ℂ )
5 binomcxplem.f 𝐹 = ( 𝑗 ∈ ℕ0 ↦ ( 𝐶 C𝑐 𝑗 ) )
6 binomcxplem.s 𝑆 = ( 𝑏 ∈ ℂ ↦ ( 𝑘 ∈ ℕ0 ↦ ( ( 𝐹𝑘 ) · ( 𝑏𝑘 ) ) ) )
7 binomcxplem.r 𝑅 = sup ( { 𝑟 ∈ ℝ ∣ seq 0 ( + , ( 𝑆𝑟 ) ) ∈ dom ⇝ } , ℝ* , < )
8 binomcxplem.e 𝐸 = ( 𝑏 ∈ ℂ ↦ ( 𝑘 ∈ ℕ ↦ ( ( 𝑘 · ( 𝐹𝑘 ) ) · ( 𝑏 ↑ ( 𝑘 − 1 ) ) ) ) )
9 binomcxplem.d 𝐷 = ( abs “ ( 0 [,) 𝑅 ) )
10 4 adantr ( ( 𝜑𝑗 ∈ ℕ0 ) → 𝐶 ∈ ℂ )
11 simpr ( ( 𝜑𝑗 ∈ ℕ0 ) → 𝑗 ∈ ℕ0 )
12 10 11 bcccl ( ( 𝜑𝑗 ∈ ℕ0 ) → ( 𝐶 C𝑐 𝑗 ) ∈ ℂ )
13 12 5 fmptd ( 𝜑𝐹 : ℕ0 ⟶ ℂ )
14 13 adantr ( ( 𝜑𝐽𝐷 ) → 𝐹 : ℕ0 ⟶ ℂ )
15 9 eleq2i ( 𝐽𝐷𝐽 ∈ ( abs “ ( 0 [,) 𝑅 ) ) )
16 absf abs : ℂ ⟶ ℝ
17 ffn ( abs : ℂ ⟶ ℝ → abs Fn ℂ )
18 elpreima ( abs Fn ℂ → ( 𝐽 ∈ ( abs “ ( 0 [,) 𝑅 ) ) ↔ ( 𝐽 ∈ ℂ ∧ ( abs ‘ 𝐽 ) ∈ ( 0 [,) 𝑅 ) ) ) )
19 16 17 18 mp2b ( 𝐽 ∈ ( abs “ ( 0 [,) 𝑅 ) ) ↔ ( 𝐽 ∈ ℂ ∧ ( abs ‘ 𝐽 ) ∈ ( 0 [,) 𝑅 ) ) )
20 15 19 bitri ( 𝐽𝐷 ↔ ( 𝐽 ∈ ℂ ∧ ( abs ‘ 𝐽 ) ∈ ( 0 [,) 𝑅 ) ) )
21 20 simplbi ( 𝐽𝐷𝐽 ∈ ℂ )
22 21 adantl ( ( 𝜑𝐽𝐷 ) → 𝐽 ∈ ℂ )
23 20 simprbi ( 𝐽𝐷 → ( abs ‘ 𝐽 ) ∈ ( 0 [,) 𝑅 ) )
24 0re 0 ∈ ℝ
25 ssrab2 { 𝑟 ∈ ℝ ∣ seq 0 ( + , ( 𝑆𝑟 ) ) ∈ dom ⇝ } ⊆ ℝ
26 ressxr ℝ ⊆ ℝ*
27 25 26 sstri { 𝑟 ∈ ℝ ∣ seq 0 ( + , ( 𝑆𝑟 ) ) ∈ dom ⇝ } ⊆ ℝ*
28 supxrcl ( { 𝑟 ∈ ℝ ∣ seq 0 ( + , ( 𝑆𝑟 ) ) ∈ dom ⇝ } ⊆ ℝ* → sup ( { 𝑟 ∈ ℝ ∣ seq 0 ( + , ( 𝑆𝑟 ) ) ∈ dom ⇝ } , ℝ* , < ) ∈ ℝ* )
29 27 28 ax-mp sup ( { 𝑟 ∈ ℝ ∣ seq 0 ( + , ( 𝑆𝑟 ) ) ∈ dom ⇝ } , ℝ* , < ) ∈ ℝ*
30 7 29 eqeltri 𝑅 ∈ ℝ*
31 elico2 ( ( 0 ∈ ℝ ∧ 𝑅 ∈ ℝ* ) → ( ( abs ‘ 𝐽 ) ∈ ( 0 [,) 𝑅 ) ↔ ( ( abs ‘ 𝐽 ) ∈ ℝ ∧ 0 ≤ ( abs ‘ 𝐽 ) ∧ ( abs ‘ 𝐽 ) < 𝑅 ) ) )
32 24 30 31 mp2an ( ( abs ‘ 𝐽 ) ∈ ( 0 [,) 𝑅 ) ↔ ( ( abs ‘ 𝐽 ) ∈ ℝ ∧ 0 ≤ ( abs ‘ 𝐽 ) ∧ ( abs ‘ 𝐽 ) < 𝑅 ) )
33 32 simp3bi ( ( abs ‘ 𝐽 ) ∈ ( 0 [,) 𝑅 ) → ( abs ‘ 𝐽 ) < 𝑅 )
34 23 33 syl ( 𝐽𝐷 → ( abs ‘ 𝐽 ) < 𝑅 )
35 34 adantl ( ( 𝜑𝐽𝐷 ) → ( abs ‘ 𝐽 ) < 𝑅 )
36 6 14 7 22 35 radcnvlt2 ( ( 𝜑𝐽𝐷 ) → seq 0 ( + , ( 𝑆𝐽 ) ) ∈ dom ⇝ )
37 8 a1i ( ( 𝜑𝐽 ∈ ℂ ) → 𝐸 = ( 𝑏 ∈ ℂ ↦ ( 𝑘 ∈ ℕ ↦ ( ( 𝑘 · ( 𝐹𝑘 ) ) · ( 𝑏 ↑ ( 𝑘 − 1 ) ) ) ) ) )
38 simplr ( ( ( ( 𝜑𝐽 ∈ ℂ ) ∧ 𝑏 = 𝐽 ) ∧ 𝑘 ∈ ℕ ) → 𝑏 = 𝐽 )
39 38 oveq1d ( ( ( ( 𝜑𝐽 ∈ ℂ ) ∧ 𝑏 = 𝐽 ) ∧ 𝑘 ∈ ℕ ) → ( 𝑏 ↑ ( 𝑘 − 1 ) ) = ( 𝐽 ↑ ( 𝑘 − 1 ) ) )
40 39 oveq2d ( ( ( ( 𝜑𝐽 ∈ ℂ ) ∧ 𝑏 = 𝐽 ) ∧ 𝑘 ∈ ℕ ) → ( ( 𝑘 · ( 𝐹𝑘 ) ) · ( 𝑏 ↑ ( 𝑘 − 1 ) ) ) = ( ( 𝑘 · ( 𝐹𝑘 ) ) · ( 𝐽 ↑ ( 𝑘 − 1 ) ) ) )
41 40 mpteq2dva ( ( ( 𝜑𝐽 ∈ ℂ ) ∧ 𝑏 = 𝐽 ) → ( 𝑘 ∈ ℕ ↦ ( ( 𝑘 · ( 𝐹𝑘 ) ) · ( 𝑏 ↑ ( 𝑘 − 1 ) ) ) ) = ( 𝑘 ∈ ℕ ↦ ( ( 𝑘 · ( 𝐹𝑘 ) ) · ( 𝐽 ↑ ( 𝑘 − 1 ) ) ) ) )
42 simpr ( ( 𝜑𝐽 ∈ ℂ ) → 𝐽 ∈ ℂ )
43 nnex ℕ ∈ V
44 43 mptex ( 𝑘 ∈ ℕ ↦ ( ( 𝑘 · ( 𝐹𝑘 ) ) · ( 𝐽 ↑ ( 𝑘 − 1 ) ) ) ) ∈ V
45 44 a1i ( ( 𝜑𝐽 ∈ ℂ ) → ( 𝑘 ∈ ℕ ↦ ( ( 𝑘 · ( 𝐹𝑘 ) ) · ( 𝐽 ↑ ( 𝑘 − 1 ) ) ) ) ∈ V )
46 37 41 42 45 fvmptd ( ( 𝜑𝐽 ∈ ℂ ) → ( 𝐸𝐽 ) = ( 𝑘 ∈ ℕ ↦ ( ( 𝑘 · ( 𝐹𝑘 ) ) · ( 𝐽 ↑ ( 𝑘 − 1 ) ) ) ) )
47 21 46 sylan2 ( ( 𝜑𝐽𝐷 ) → ( 𝐸𝐽 ) = ( 𝑘 ∈ ℕ ↦ ( ( 𝑘 · ( 𝐹𝑘 ) ) · ( 𝐽 ↑ ( 𝑘 − 1 ) ) ) ) )
48 47 seqeq3d ( ( 𝜑𝐽𝐷 ) → seq 1 ( + , ( 𝐸𝐽 ) ) = seq 1 ( + , ( 𝑘 ∈ ℕ ↦ ( ( 𝑘 · ( 𝐹𝑘 ) ) · ( 𝐽 ↑ ( 𝑘 − 1 ) ) ) ) ) )
49 eqid ( 𝑘 ∈ ℕ ↦ ( ( 𝑘 · ( 𝐹𝑘 ) ) · ( 𝐽 ↑ ( 𝑘 − 1 ) ) ) ) = ( 𝑘 ∈ ℕ ↦ ( ( 𝑘 · ( 𝐹𝑘 ) ) · ( 𝐽 ↑ ( 𝑘 − 1 ) ) ) )
50 6 7 49 14 22 35 dvradcnv2 ( ( 𝜑𝐽𝐷 ) → seq 1 ( + , ( 𝑘 ∈ ℕ ↦ ( ( 𝑘 · ( 𝐹𝑘 ) ) · ( 𝐽 ↑ ( 𝑘 − 1 ) ) ) ) ) ∈ dom ⇝ )
51 48 50 eqeltrd ( ( 𝜑𝐽𝐷 ) → seq 1 ( + , ( 𝐸𝐽 ) ) ∈ dom ⇝ )
52 36 51 jca ( ( 𝜑𝐽𝐷 ) → ( seq 0 ( + , ( 𝑆𝐽 ) ) ∈ dom ⇝ ∧ seq 1 ( + , ( 𝐸𝐽 ) ) ∈ dom ⇝ ) )