| Step | Hyp | Ref | Expression | 
						
							| 1 |  | pnfxr | ⊢ +∞  ∈  ℝ* | 
						
							| 2 |  | icossre | ⊢ ( ( 𝐴  ∈  ℝ  ∧  +∞  ∈  ℝ* )  →  ( 𝐴 [,) +∞ )  ⊆  ℝ ) | 
						
							| 3 | 1 2 | mpan2 | ⊢ ( 𝐴  ∈  ℝ  →  ( 𝐴 [,) +∞ )  ⊆  ℝ ) | 
						
							| 4 | 3 | adantr | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( 𝐴 [,) +∞ )  ⊆  ℝ ) | 
						
							| 5 |  | ovolge0 | ⊢ ( ( 𝐴 [,) +∞ )  ⊆  ℝ  →  0  ≤  ( vol* ‘ ( 𝐴 [,) +∞ ) ) ) | 
						
							| 6 | 4 5 | syl | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  0  ≤  ( vol* ‘ ( 𝐴 [,) +∞ ) ) ) | 
						
							| 7 |  | mnflt0 | ⊢ -∞  <  0 | 
						
							| 8 |  | mnfxr | ⊢ -∞  ∈  ℝ* | 
						
							| 9 |  | 0xr | ⊢ 0  ∈  ℝ* | 
						
							| 10 |  | ovolcl | ⊢ ( ( 𝐴 [,) +∞ )  ⊆  ℝ  →  ( vol* ‘ ( 𝐴 [,) +∞ ) )  ∈  ℝ* ) | 
						
							| 11 | 3 10 | syl | ⊢ ( 𝐴  ∈  ℝ  →  ( vol* ‘ ( 𝐴 [,) +∞ ) )  ∈  ℝ* ) | 
						
							| 12 | 11 | adantr | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( vol* ‘ ( 𝐴 [,) +∞ ) )  ∈  ℝ* ) | 
						
							| 13 |  | xrltletr | ⊢ ( ( -∞  ∈  ℝ*  ∧  0  ∈  ℝ*  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  ∈  ℝ* )  →  ( ( -∞  <  0  ∧  0  ≤  ( vol* ‘ ( 𝐴 [,) +∞ ) ) )  →  -∞  <  ( vol* ‘ ( 𝐴 [,) +∞ ) ) ) ) | 
						
							| 14 | 8 9 12 13 | mp3an12i | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( ( -∞  <  0  ∧  0  ≤  ( vol* ‘ ( 𝐴 [,) +∞ ) ) )  →  -∞  <  ( vol* ‘ ( 𝐴 [,) +∞ ) ) ) ) | 
						
							| 15 | 7 14 | mpani | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( 0  ≤  ( vol* ‘ ( 𝐴 [,) +∞ ) )  →  -∞  <  ( vol* ‘ ( 𝐴 [,) +∞ ) ) ) ) | 
						
							| 16 | 6 15 | mpd | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  -∞  <  ( vol* ‘ ( 𝐴 [,) +∞ ) ) ) | 
						
							| 17 |  | simpr | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ ) | 
						
							| 18 |  | xrrebnd | ⊢ ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  ∈  ℝ*  →  ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  ∈  ℝ  ↔  ( -∞  <  ( vol* ‘ ( 𝐴 [,) +∞ ) )  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ ) ) ) | 
						
							| 19 | 12 18 | syl | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  ∈  ℝ  ↔  ( -∞  <  ( vol* ‘ ( 𝐴 [,) +∞ ) )  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ ) ) ) | 
						
							| 20 | 16 17 19 | mpbir2and | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( vol* ‘ ( 𝐴 [,) +∞ ) )  ∈  ℝ ) | 
						
							| 21 | 20 | ltp1d | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 ) ) | 
						
							| 22 |  | peano2re | ⊢ ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  ∈  ℝ  →  ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  ∈  ℝ ) | 
						
							| 23 | 20 22 | syl | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  ∈  ℝ ) | 
						
							| 24 |  | simpl | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  𝐴  ∈  ℝ ) | 
						
							| 25 | 23 24 | readdcld | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 )  ∈  ℝ ) | 
						
							| 26 |  | 0red | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  0  ∈  ℝ ) | 
						
							| 27 | 20 | lep1d | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( vol* ‘ ( 𝐴 [,) +∞ ) )  ≤  ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 ) ) | 
						
							| 28 | 26 20 23 6 27 | letrd | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  0  ≤  ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 ) ) | 
						
							| 29 | 24 23 | addge02d | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( 0  ≤  ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  ↔  𝐴  ≤  ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) ) ) | 
						
							| 30 | 28 29 | mpbid | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  𝐴  ≤  ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) ) | 
						
							| 31 |  | ovolicc | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 )  ∈  ℝ  ∧  𝐴  ≤  ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) )  →  ( vol* ‘ ( 𝐴 [,] ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) ) )  =  ( ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 )  −  𝐴 ) ) | 
						
							| 32 | 24 25 30 31 | syl3anc | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( vol* ‘ ( 𝐴 [,] ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) ) )  =  ( ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 )  −  𝐴 ) ) | 
						
							| 33 | 23 | recnd | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  ∈  ℂ ) | 
						
							| 34 | 24 | recnd | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  𝐴  ∈  ℂ ) | 
						
							| 35 | 33 34 | pncand | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 )  −  𝐴 )  =  ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 ) ) | 
						
							| 36 | 32 35 | eqtrd | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( vol* ‘ ( 𝐴 [,] ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) ) )  =  ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 ) ) | 
						
							| 37 |  | elicc2 | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 )  ∈  ℝ )  →  ( 𝑥  ∈  ( 𝐴 [,] ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) )  ↔  ( 𝑥  ∈  ℝ  ∧  𝐴  ≤  𝑥  ∧  𝑥  ≤  ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) ) ) ) | 
						
							| 38 | 24 25 37 | syl2anc | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( 𝑥  ∈  ( 𝐴 [,] ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) )  ↔  ( 𝑥  ∈  ℝ  ∧  𝐴  ≤  𝑥  ∧  𝑥  ≤  ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) ) ) ) | 
						
							| 39 | 38 | biimpa | ⊢ ( ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  ∧  𝑥  ∈  ( 𝐴 [,] ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) ) )  →  ( 𝑥  ∈  ℝ  ∧  𝐴  ≤  𝑥  ∧  𝑥  ≤  ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) ) ) | 
						
							| 40 | 39 | simp1d | ⊢ ( ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  ∧  𝑥  ∈  ( 𝐴 [,] ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) ) )  →  𝑥  ∈  ℝ ) | 
						
							| 41 | 39 | simp2d | ⊢ ( ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  ∧  𝑥  ∈  ( 𝐴 [,] ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) ) )  →  𝐴  ≤  𝑥 ) | 
						
							| 42 |  | elicopnf | ⊢ ( 𝐴  ∈  ℝ  →  ( 𝑥  ∈  ( 𝐴 [,) +∞ )  ↔  ( 𝑥  ∈  ℝ  ∧  𝐴  ≤  𝑥 ) ) ) | 
						
							| 43 | 42 | ad2antrr | ⊢ ( ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  ∧  𝑥  ∈  ( 𝐴 [,] ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) ) )  →  ( 𝑥  ∈  ( 𝐴 [,) +∞ )  ↔  ( 𝑥  ∈  ℝ  ∧  𝐴  ≤  𝑥 ) ) ) | 
						
							| 44 | 40 41 43 | mpbir2and | ⊢ ( ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  ∧  𝑥  ∈  ( 𝐴 [,] ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) ) )  →  𝑥  ∈  ( 𝐴 [,) +∞ ) ) | 
						
							| 45 | 44 | ex | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( 𝑥  ∈  ( 𝐴 [,] ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) )  →  𝑥  ∈  ( 𝐴 [,) +∞ ) ) ) | 
						
							| 46 | 45 | ssrdv | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( 𝐴 [,] ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) )  ⊆  ( 𝐴 [,) +∞ ) ) | 
						
							| 47 |  | ovolss | ⊢ ( ( ( 𝐴 [,] ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) )  ⊆  ( 𝐴 [,) +∞ )  ∧  ( 𝐴 [,) +∞ )  ⊆  ℝ )  →  ( vol* ‘ ( 𝐴 [,] ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) ) )  ≤  ( vol* ‘ ( 𝐴 [,) +∞ ) ) ) | 
						
							| 48 | 46 4 47 | syl2anc | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( vol* ‘ ( 𝐴 [,] ( ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  +  𝐴 ) ) )  ≤  ( vol* ‘ ( 𝐴 [,) +∞ ) ) ) | 
						
							| 49 | 36 48 | eqbrtrrd | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 )  ≤  ( vol* ‘ ( 𝐴 [,) +∞ ) ) ) | 
						
							| 50 | 23 20 49 | lensymd | ⊢ ( ( 𝐴  ∈  ℝ  ∧  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ )  →  ¬  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  +  1 ) ) | 
						
							| 51 | 21 50 | pm2.65da | ⊢ ( 𝐴  ∈  ℝ  →  ¬  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ ) | 
						
							| 52 |  | nltpnft | ⊢ ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  ∈  ℝ*  →  ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  =  +∞  ↔  ¬  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ ) ) | 
						
							| 53 | 11 52 | syl | ⊢ ( 𝐴  ∈  ℝ  →  ( ( vol* ‘ ( 𝐴 [,) +∞ ) )  =  +∞  ↔  ¬  ( vol* ‘ ( 𝐴 [,) +∞ ) )  <  +∞ ) ) | 
						
							| 54 | 51 53 | mpbird | ⊢ ( 𝐴  ∈  ℝ  →  ( vol* ‘ ( 𝐴 [,) +∞ ) )  =  +∞ ) |