| Step | Hyp | Ref | Expression | 
						
							| 1 |  | atantayl2.1 | ⊢ 𝐹  =  ( 𝑛  ∈  ℕ  ↦  if ( 2  ∥  𝑛 ,  0 ,  ( ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) )  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) ) ) ) | 
						
							| 2 |  | ax-icn | ⊢ i  ∈  ℂ | 
						
							| 3 | 2 | negcli | ⊢ - i  ∈  ℂ | 
						
							| 4 | 3 | a1i | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  - i  ∈  ℂ ) | 
						
							| 5 |  | nnnn0 | ⊢ ( 𝑛  ∈  ℕ  →  𝑛  ∈  ℕ0 ) | 
						
							| 6 | 5 | ad2antlr | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  𝑛  ∈  ℕ0 ) | 
						
							| 7 | 4 6 | expcld | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( - i ↑ 𝑛 )  ∈  ℂ ) | 
						
							| 8 |  | sqneg | ⊢ ( i  ∈  ℂ  →  ( - i ↑ 2 )  =  ( i ↑ 2 ) ) | 
						
							| 9 | 2 8 | ax-mp | ⊢ ( - i ↑ 2 )  =  ( i ↑ 2 ) | 
						
							| 10 | 9 | oveq1i | ⊢ ( ( - i ↑ 2 ) ↑ ( 𝑛  /  2 ) )  =  ( ( i ↑ 2 ) ↑ ( 𝑛  /  2 ) ) | 
						
							| 11 |  | ine0 | ⊢ i  ≠  0 | 
						
							| 12 | 2 11 | negne0i | ⊢ - i  ≠  0 | 
						
							| 13 | 12 | a1i | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  - i  ≠  0 ) | 
						
							| 14 |  | 2z | ⊢ 2  ∈  ℤ | 
						
							| 15 | 14 | a1i | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  2  ∈  ℤ ) | 
						
							| 16 |  | 2ne0 | ⊢ 2  ≠  0 | 
						
							| 17 |  | nnz | ⊢ ( 𝑛  ∈  ℕ  →  𝑛  ∈  ℤ ) | 
						
							| 18 | 17 | adantl | ⊢ ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  →  𝑛  ∈  ℤ ) | 
						
							| 19 |  | dvdsval2 | ⊢ ( ( 2  ∈  ℤ  ∧  2  ≠  0  ∧  𝑛  ∈  ℤ )  →  ( 2  ∥  𝑛  ↔  ( 𝑛  /  2 )  ∈  ℤ ) ) | 
						
							| 20 | 14 16 18 19 | mp3an12i | ⊢ ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  →  ( 2  ∥  𝑛  ↔  ( 𝑛  /  2 )  ∈  ℤ ) ) | 
						
							| 21 | 20 | biimpa | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( 𝑛  /  2 )  ∈  ℤ ) | 
						
							| 22 |  | expmulz | ⊢ ( ( ( - i  ∈  ℂ  ∧  - i  ≠  0 )  ∧  ( 2  ∈  ℤ  ∧  ( 𝑛  /  2 )  ∈  ℤ ) )  →  ( - i ↑ ( 2  ·  ( 𝑛  /  2 ) ) )  =  ( ( - i ↑ 2 ) ↑ ( 𝑛  /  2 ) ) ) | 
						
							| 23 | 4 13 15 21 22 | syl22anc | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( - i ↑ ( 2  ·  ( 𝑛  /  2 ) ) )  =  ( ( - i ↑ 2 ) ↑ ( 𝑛  /  2 ) ) ) | 
						
							| 24 | 2 | a1i | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  i  ∈  ℂ ) | 
						
							| 25 | 11 | a1i | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  i  ≠  0 ) | 
						
							| 26 |  | expmulz | ⊢ ( ( ( i  ∈  ℂ  ∧  i  ≠  0 )  ∧  ( 2  ∈  ℤ  ∧  ( 𝑛  /  2 )  ∈  ℤ ) )  →  ( i ↑ ( 2  ·  ( 𝑛  /  2 ) ) )  =  ( ( i ↑ 2 ) ↑ ( 𝑛  /  2 ) ) ) | 
						
							| 27 | 24 25 15 21 26 | syl22anc | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( i ↑ ( 2  ·  ( 𝑛  /  2 ) ) )  =  ( ( i ↑ 2 ) ↑ ( 𝑛  /  2 ) ) ) | 
						
							| 28 | 10 23 27 | 3eqtr4a | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( - i ↑ ( 2  ·  ( 𝑛  /  2 ) ) )  =  ( i ↑ ( 2  ·  ( 𝑛  /  2 ) ) ) ) | 
						
							| 29 |  | nncn | ⊢ ( 𝑛  ∈  ℕ  →  𝑛  ∈  ℂ ) | 
						
							| 30 | 29 | ad2antlr | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  𝑛  ∈  ℂ ) | 
						
							| 31 |  | 2cnd | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  2  ∈  ℂ ) | 
						
							| 32 | 16 | a1i | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  2  ≠  0 ) | 
						
							| 33 | 30 31 32 | divcan2d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( 2  ·  ( 𝑛  /  2 ) )  =  𝑛 ) | 
						
							| 34 | 33 | oveq2d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( - i ↑ ( 2  ·  ( 𝑛  /  2 ) ) )  =  ( - i ↑ 𝑛 ) ) | 
						
							| 35 | 33 | oveq2d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( i ↑ ( 2  ·  ( 𝑛  /  2 ) ) )  =  ( i ↑ 𝑛 ) ) | 
						
							| 36 | 28 34 35 | 3eqtr3d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( - i ↑ 𝑛 )  =  ( i ↑ 𝑛 ) ) | 
						
							| 37 | 7 36 | subeq0bd | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) )  =  0 ) | 
						
							| 38 | 37 | oveq2d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  =  ( i  ·  0 ) ) | 
						
							| 39 |  | it0e0 | ⊢ ( i  ·  0 )  =  0 | 
						
							| 40 | 38 39 | eqtrdi | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  =  0 ) | 
						
							| 41 | 40 | oveq1d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  /  2 )  =  ( 0  /  2 ) ) | 
						
							| 42 |  | 2cn | ⊢ 2  ∈  ℂ | 
						
							| 43 | 42 16 | div0i | ⊢ ( 0  /  2 )  =  0 | 
						
							| 44 | 41 43 | eqtrdi | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  /  2 )  =  0 ) | 
						
							| 45 | 44 | oveq1d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( ( ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  /  2 )  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) )  =  ( 0  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) ) ) | 
						
							| 46 |  | simplll | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  𝐴  ∈  ℂ ) | 
						
							| 47 | 46 6 | expcld | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( 𝐴 ↑ 𝑛 )  ∈  ℂ ) | 
						
							| 48 |  | nnne0 | ⊢ ( 𝑛  ∈  ℕ  →  𝑛  ≠  0 ) | 
						
							| 49 | 48 | ad2antlr | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  𝑛  ≠  0 ) | 
						
							| 50 | 47 30 49 | divcld | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 )  ∈  ℂ ) | 
						
							| 51 | 50 | mul02d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  ( 0  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) )  =  0 ) | 
						
							| 52 | 45 51 | eqtr2d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  2  ∥  𝑛 )  →  0  =  ( ( ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  /  2 )  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) ) ) | 
						
							| 53 |  | 2cnd | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  2  ∈  ℂ ) | 
						
							| 54 |  | ax-1cn | ⊢ 1  ∈  ℂ | 
						
							| 55 | 54 | negcli | ⊢ - 1  ∈  ℂ | 
						
							| 56 | 55 | a1i | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  - 1  ∈  ℂ ) | 
						
							| 57 |  | neg1ne0 | ⊢ - 1  ≠  0 | 
						
							| 58 | 57 | a1i | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  - 1  ≠  0 ) | 
						
							| 59 | 29 | ad2antlr | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  𝑛  ∈  ℂ ) | 
						
							| 60 |  | peano2cn | ⊢ ( 𝑛  ∈  ℂ  →  ( 𝑛  +  1 )  ∈  ℂ ) | 
						
							| 61 | 59 60 | syl | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( 𝑛  +  1 )  ∈  ℂ ) | 
						
							| 62 | 16 | a1i | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  2  ≠  0 ) | 
						
							| 63 | 61 53 53 62 | divsubdird | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( ( 𝑛  +  1 )  −  2 )  /  2 )  =  ( ( ( 𝑛  +  1 )  /  2 )  −  ( 2  /  2 ) ) ) | 
						
							| 64 |  | 2div2e1 | ⊢ ( 2  /  2 )  =  1 | 
						
							| 65 | 64 | oveq2i | ⊢ ( ( ( 𝑛  +  1 )  /  2 )  −  ( 2  /  2 ) )  =  ( ( ( 𝑛  +  1 )  /  2 )  −  1 ) | 
						
							| 66 | 63 65 | eqtrdi | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( ( 𝑛  +  1 )  −  2 )  /  2 )  =  ( ( ( 𝑛  +  1 )  /  2 )  −  1 ) ) | 
						
							| 67 |  | df-2 | ⊢ 2  =  ( 1  +  1 ) | 
						
							| 68 | 67 | oveq2i | ⊢ ( ( 𝑛  +  1 )  −  2 )  =  ( ( 𝑛  +  1 )  −  ( 1  +  1 ) ) | 
						
							| 69 | 54 | a1i | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  1  ∈  ℂ ) | 
						
							| 70 | 59 69 69 | pnpcan2d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( 𝑛  +  1 )  −  ( 1  +  1 ) )  =  ( 𝑛  −  1 ) ) | 
						
							| 71 | 68 70 | eqtrid | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( 𝑛  +  1 )  −  2 )  =  ( 𝑛  −  1 ) ) | 
						
							| 72 | 71 | oveq1d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( ( 𝑛  +  1 )  −  2 )  /  2 )  =  ( ( 𝑛  −  1 )  /  2 ) ) | 
						
							| 73 | 66 72 | eqtr3d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( ( 𝑛  +  1 )  /  2 )  −  1 )  =  ( ( 𝑛  −  1 )  /  2 ) ) | 
						
							| 74 | 20 | notbid | ⊢ ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  →  ( ¬  2  ∥  𝑛  ↔  ¬  ( 𝑛  /  2 )  ∈  ℤ ) ) | 
						
							| 75 |  | zeo | ⊢ ( 𝑛  ∈  ℤ  →  ( ( 𝑛  /  2 )  ∈  ℤ  ∨  ( ( 𝑛  +  1 )  /  2 )  ∈  ℤ ) ) | 
						
							| 76 | 18 75 | syl | ⊢ ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  →  ( ( 𝑛  /  2 )  ∈  ℤ  ∨  ( ( 𝑛  +  1 )  /  2 )  ∈  ℤ ) ) | 
						
							| 77 | 76 | ord | ⊢ ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  →  ( ¬  ( 𝑛  /  2 )  ∈  ℤ  →  ( ( 𝑛  +  1 )  /  2 )  ∈  ℤ ) ) | 
						
							| 78 | 74 77 | sylbid | ⊢ ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  →  ( ¬  2  ∥  𝑛  →  ( ( 𝑛  +  1 )  /  2 )  ∈  ℤ ) ) | 
						
							| 79 | 78 | imp | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( 𝑛  +  1 )  /  2 )  ∈  ℤ ) | 
						
							| 80 |  | peano2zm | ⊢ ( ( ( 𝑛  +  1 )  /  2 )  ∈  ℤ  →  ( ( ( 𝑛  +  1 )  /  2 )  −  1 )  ∈  ℤ ) | 
						
							| 81 | 79 80 | syl | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( ( 𝑛  +  1 )  /  2 )  −  1 )  ∈  ℤ ) | 
						
							| 82 | 73 81 | eqeltrrd | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( 𝑛  −  1 )  /  2 )  ∈  ℤ ) | 
						
							| 83 | 56 58 82 | expclzd | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) )  ∈  ℂ ) | 
						
							| 84 | 83 | 2timesd | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( 2  ·  ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) ) )  =  ( ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) )  +  ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) ) ) ) | 
						
							| 85 |  | subcl | ⊢ ( ( 𝑛  ∈  ℂ  ∧  1  ∈  ℂ )  →  ( 𝑛  −  1 )  ∈  ℂ ) | 
						
							| 86 | 59 54 85 | sylancl | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( 𝑛  −  1 )  ∈  ℂ ) | 
						
							| 87 | 86 53 62 | divcan2d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( 2  ·  ( ( 𝑛  −  1 )  /  2 ) )  =  ( 𝑛  −  1 ) ) | 
						
							| 88 | 87 | oveq2d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( - i ↑ ( 2  ·  ( ( 𝑛  −  1 )  /  2 ) ) )  =  ( - i ↑ ( 𝑛  −  1 ) ) ) | 
						
							| 89 | 3 | a1i | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  - i  ∈  ℂ ) | 
						
							| 90 | 12 | a1i | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  - i  ≠  0 ) | 
						
							| 91 | 17 | ad2antlr | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  𝑛  ∈  ℤ ) | 
						
							| 92 | 89 90 91 | expm1d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( - i ↑ ( 𝑛  −  1 ) )  =  ( ( - i ↑ 𝑛 )  /  - i ) ) | 
						
							| 93 | 88 92 | eqtrd | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( - i ↑ ( 2  ·  ( ( 𝑛  −  1 )  /  2 ) ) )  =  ( ( - i ↑ 𝑛 )  /  - i ) ) | 
						
							| 94 | 14 | a1i | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  2  ∈  ℤ ) | 
						
							| 95 |  | expmulz | ⊢ ( ( ( - i  ∈  ℂ  ∧  - i  ≠  0 )  ∧  ( 2  ∈  ℤ  ∧  ( ( 𝑛  −  1 )  /  2 )  ∈  ℤ ) )  →  ( - i ↑ ( 2  ·  ( ( 𝑛  −  1 )  /  2 ) ) )  =  ( ( - i ↑ 2 ) ↑ ( ( 𝑛  −  1 )  /  2 ) ) ) | 
						
							| 96 | 89 90 94 82 95 | syl22anc | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( - i ↑ ( 2  ·  ( ( 𝑛  −  1 )  /  2 ) ) )  =  ( ( - i ↑ 2 ) ↑ ( ( 𝑛  −  1 )  /  2 ) ) ) | 
						
							| 97 | 5 | ad2antlr | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  𝑛  ∈  ℕ0 ) | 
						
							| 98 |  | expcl | ⊢ ( ( - i  ∈  ℂ  ∧  𝑛  ∈  ℕ0 )  →  ( - i ↑ 𝑛 )  ∈  ℂ ) | 
						
							| 99 | 3 97 98 | sylancr | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( - i ↑ 𝑛 )  ∈  ℂ ) | 
						
							| 100 | 99 89 90 | divrec2d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( - i ↑ 𝑛 )  /  - i )  =  ( ( 1  /  - i )  ·  ( - i ↑ 𝑛 ) ) ) | 
						
							| 101 | 93 96 100 | 3eqtr3d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( - i ↑ 2 ) ↑ ( ( 𝑛  −  1 )  /  2 ) )  =  ( ( 1  /  - i )  ·  ( - i ↑ 𝑛 ) ) ) | 
						
							| 102 |  | i2 | ⊢ ( i ↑ 2 )  =  - 1 | 
						
							| 103 | 9 102 | eqtri | ⊢ ( - i ↑ 2 )  =  - 1 | 
						
							| 104 | 103 | oveq1i | ⊢ ( ( - i ↑ 2 ) ↑ ( ( 𝑛  −  1 )  /  2 ) )  =  ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) ) | 
						
							| 105 |  | irec | ⊢ ( 1  /  i )  =  - i | 
						
							| 106 | 105 | negeqi | ⊢ - ( 1  /  i )  =  - - i | 
						
							| 107 |  | divneg2 | ⊢ ( ( 1  ∈  ℂ  ∧  i  ∈  ℂ  ∧  i  ≠  0 )  →  - ( 1  /  i )  =  ( 1  /  - i ) ) | 
						
							| 108 | 54 2 11 107 | mp3an | ⊢ - ( 1  /  i )  =  ( 1  /  - i ) | 
						
							| 109 | 2 | negnegi | ⊢ - - i  =  i | 
						
							| 110 | 106 108 109 | 3eqtr3i | ⊢ ( 1  /  - i )  =  i | 
						
							| 111 | 110 | oveq1i | ⊢ ( ( 1  /  - i )  ·  ( - i ↑ 𝑛 ) )  =  ( i  ·  ( - i ↑ 𝑛 ) ) | 
						
							| 112 | 101 104 111 | 3eqtr3g | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) )  =  ( i  ·  ( - i ↑ 𝑛 ) ) ) | 
						
							| 113 | 87 | oveq2d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( i ↑ ( 2  ·  ( ( 𝑛  −  1 )  /  2 ) ) )  =  ( i ↑ ( 𝑛  −  1 ) ) ) | 
						
							| 114 | 2 | a1i | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  i  ∈  ℂ ) | 
						
							| 115 | 11 | a1i | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  i  ≠  0 ) | 
						
							| 116 | 114 115 91 | expm1d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( i ↑ ( 𝑛  −  1 ) )  =  ( ( i ↑ 𝑛 )  /  i ) ) | 
						
							| 117 | 113 116 | eqtrd | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( i ↑ ( 2  ·  ( ( 𝑛  −  1 )  /  2 ) ) )  =  ( ( i ↑ 𝑛 )  /  i ) ) | 
						
							| 118 |  | expmulz | ⊢ ( ( ( i  ∈  ℂ  ∧  i  ≠  0 )  ∧  ( 2  ∈  ℤ  ∧  ( ( 𝑛  −  1 )  /  2 )  ∈  ℤ ) )  →  ( i ↑ ( 2  ·  ( ( 𝑛  −  1 )  /  2 ) ) )  =  ( ( i ↑ 2 ) ↑ ( ( 𝑛  −  1 )  /  2 ) ) ) | 
						
							| 119 | 114 115 94 82 118 | syl22anc | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( i ↑ ( 2  ·  ( ( 𝑛  −  1 )  /  2 ) ) )  =  ( ( i ↑ 2 ) ↑ ( ( 𝑛  −  1 )  /  2 ) ) ) | 
						
							| 120 |  | expcl | ⊢ ( ( i  ∈  ℂ  ∧  𝑛  ∈  ℕ0 )  →  ( i ↑ 𝑛 )  ∈  ℂ ) | 
						
							| 121 | 2 97 120 | sylancr | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( i ↑ 𝑛 )  ∈  ℂ ) | 
						
							| 122 | 121 114 115 | divrec2d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( i ↑ 𝑛 )  /  i )  =  ( ( 1  /  i )  ·  ( i ↑ 𝑛 ) ) ) | 
						
							| 123 | 117 119 122 | 3eqtr3d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( i ↑ 2 ) ↑ ( ( 𝑛  −  1 )  /  2 ) )  =  ( ( 1  /  i )  ·  ( i ↑ 𝑛 ) ) ) | 
						
							| 124 | 102 | oveq1i | ⊢ ( ( i ↑ 2 ) ↑ ( ( 𝑛  −  1 )  /  2 ) )  =  ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) ) | 
						
							| 125 | 105 | oveq1i | ⊢ ( ( 1  /  i )  ·  ( i ↑ 𝑛 ) )  =  ( - i  ·  ( i ↑ 𝑛 ) ) | 
						
							| 126 | 123 124 125 | 3eqtr3g | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) )  =  ( - i  ·  ( i ↑ 𝑛 ) ) ) | 
						
							| 127 |  | mulneg1 | ⊢ ( ( i  ∈  ℂ  ∧  ( i ↑ 𝑛 )  ∈  ℂ )  →  ( - i  ·  ( i ↑ 𝑛 ) )  =  - ( i  ·  ( i ↑ 𝑛 ) ) ) | 
						
							| 128 | 2 121 127 | sylancr | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( - i  ·  ( i ↑ 𝑛 ) )  =  - ( i  ·  ( i ↑ 𝑛 ) ) ) | 
						
							| 129 | 126 128 | eqtrd | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) )  =  - ( i  ·  ( i ↑ 𝑛 ) ) ) | 
						
							| 130 | 112 129 | oveq12d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) )  +  ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) ) )  =  ( ( i  ·  ( - i ↑ 𝑛 ) )  +  - ( i  ·  ( i ↑ 𝑛 ) ) ) ) | 
						
							| 131 |  | mulcl | ⊢ ( ( i  ∈  ℂ  ∧  ( - i ↑ 𝑛 )  ∈  ℂ )  →  ( i  ·  ( - i ↑ 𝑛 ) )  ∈  ℂ ) | 
						
							| 132 | 2 99 131 | sylancr | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( i  ·  ( - i ↑ 𝑛 ) )  ∈  ℂ ) | 
						
							| 133 |  | mulcl | ⊢ ( ( i  ∈  ℂ  ∧  ( i ↑ 𝑛 )  ∈  ℂ )  →  ( i  ·  ( i ↑ 𝑛 ) )  ∈  ℂ ) | 
						
							| 134 | 2 121 133 | sylancr | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( i  ·  ( i ↑ 𝑛 ) )  ∈  ℂ ) | 
						
							| 135 | 132 134 | negsubd | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( i  ·  ( - i ↑ 𝑛 ) )  +  - ( i  ·  ( i ↑ 𝑛 ) ) )  =  ( ( i  ·  ( - i ↑ 𝑛 ) )  −  ( i  ·  ( i ↑ 𝑛 ) ) ) ) | 
						
							| 136 | 114 99 121 | subdid | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  =  ( ( i  ·  ( - i ↑ 𝑛 ) )  −  ( i  ·  ( i ↑ 𝑛 ) ) ) ) | 
						
							| 137 | 135 136 | eqtr4d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( i  ·  ( - i ↑ 𝑛 ) )  +  - ( i  ·  ( i ↑ 𝑛 ) ) )  =  ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) ) ) | 
						
							| 138 | 84 130 137 | 3eqtrd | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( 2  ·  ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) ) )  =  ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) ) ) | 
						
							| 139 | 53 83 62 138 | mvllmuld | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) )  =  ( ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  /  2 ) ) | 
						
							| 140 | 139 | oveq1d | ⊢ ( ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  ∧  ¬  2  ∥  𝑛 )  →  ( ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) )  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) )  =  ( ( ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  /  2 )  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) ) ) | 
						
							| 141 | 52 140 | ifeqda | ⊢ ( ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  ∧  𝑛  ∈  ℕ )  →  if ( 2  ∥  𝑛 ,  0 ,  ( ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) )  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) ) )  =  ( ( ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  /  2 )  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) ) ) | 
						
							| 142 | 141 | mpteq2dva | ⊢ ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  →  ( 𝑛  ∈  ℕ  ↦  if ( 2  ∥  𝑛 ,  0 ,  ( ( - 1 ↑ ( ( 𝑛  −  1 )  /  2 ) )  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) ) ) )  =  ( 𝑛  ∈  ℕ  ↦  ( ( ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  /  2 )  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) ) ) ) | 
						
							| 143 | 1 142 | eqtrid | ⊢ ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  →  𝐹  =  ( 𝑛  ∈  ℕ  ↦  ( ( ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  /  2 )  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) ) ) ) | 
						
							| 144 | 143 | seqeq3d | ⊢ ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  →  seq 1 (  +  ,  𝐹 )  =  seq 1 (  +  ,  ( 𝑛  ∈  ℕ  ↦  ( ( ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  /  2 )  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) ) ) ) ) | 
						
							| 145 |  | eqid | ⊢ ( 𝑛  ∈  ℕ  ↦  ( ( ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  /  2 )  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) ) )  =  ( 𝑛  ∈  ℕ  ↦  ( ( ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  /  2 )  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) ) ) | 
						
							| 146 | 145 | atantayl | ⊢ ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  →  seq 1 (  +  ,  ( 𝑛  ∈  ℕ  ↦  ( ( ( i  ·  ( ( - i ↑ 𝑛 )  −  ( i ↑ 𝑛 ) ) )  /  2 )  ·  ( ( 𝐴 ↑ 𝑛 )  /  𝑛 ) ) ) )  ⇝  ( arctan ‘ 𝐴 ) ) | 
						
							| 147 | 144 146 | eqbrtrd | ⊢ ( ( 𝐴  ∈  ℂ  ∧  ( abs ‘ 𝐴 )  <  1 )  →  seq 1 (  +  ,  𝐹 )  ⇝  ( arctan ‘ 𝐴 ) ) |