| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ex-fpar.h | ⊢ 𝐻  =  ( ( ◡ ( 1st   ↾  ( V  ×  V ) )  ∘  ( 𝐹  ∘  ( 1st   ↾  ( V  ×  V ) ) ) )  ∩  ( ◡ ( 2nd   ↾  ( V  ×  V ) )  ∘  ( 𝐺  ∘  ( 2nd   ↾  ( V  ×  V ) ) ) ) ) | 
						
							| 2 |  | ex-fpar.a | ⊢ 𝐴  =  ( 0 [,) +∞ ) | 
						
							| 3 |  | ex-fpar.b | ⊢ 𝐵  =  ℝ | 
						
							| 4 |  | ex-fpar.f | ⊢ 𝐹  =  ( √  ↾  𝐴 ) | 
						
							| 5 |  | ex-fpar.g | ⊢ 𝐺  =  ( sin  ↾  𝐵 ) | 
						
							| 6 |  | df-ov | ⊢ ( 𝑋 (  +   ∘  𝐻 ) 𝑌 )  =  ( (  +   ∘  𝐻 ) ‘ 〈 𝑋 ,  𝑌 〉 ) | 
						
							| 7 |  | sqrtf | ⊢ √ : ℂ ⟶ ℂ | 
						
							| 8 |  | ffn | ⊢ ( √ : ℂ ⟶ ℂ  →  √  Fn  ℂ ) | 
						
							| 9 | 7 8 | ax-mp | ⊢ √  Fn  ℂ | 
						
							| 10 |  | rge0ssre | ⊢ ( 0 [,) +∞ )  ⊆  ℝ | 
						
							| 11 |  | ax-resscn | ⊢ ℝ  ⊆  ℂ | 
						
							| 12 | 10 11 | sstri | ⊢ ( 0 [,) +∞ )  ⊆  ℂ | 
						
							| 13 |  | fnssres | ⊢ ( ( √  Fn  ℂ  ∧  ( 0 [,) +∞ )  ⊆  ℂ )  →  ( √  ↾  ( 0 [,) +∞ ) )  Fn  ( 0 [,) +∞ ) ) | 
						
							| 14 | 2 | reseq2i | ⊢ ( √  ↾  𝐴 )  =  ( √  ↾  ( 0 [,) +∞ ) ) | 
						
							| 15 | 14 | fneq1i | ⊢ ( ( √  ↾  𝐴 )  Fn  ( 0 [,) +∞ )  ↔  ( √  ↾  ( 0 [,) +∞ ) )  Fn  ( 0 [,) +∞ ) ) | 
						
							| 16 | 13 15 | sylibr | ⊢ ( ( √  Fn  ℂ  ∧  ( 0 [,) +∞ )  ⊆  ℂ )  →  ( √  ↾  𝐴 )  Fn  ( 0 [,) +∞ ) ) | 
						
							| 17 | 9 12 16 | mp2an | ⊢ ( √  ↾  𝐴 )  Fn  ( 0 [,) +∞ ) | 
						
							| 18 |  | id | ⊢ ( 𝐹  =  ( √  ↾  𝐴 )  →  𝐹  =  ( √  ↾  𝐴 ) ) | 
						
							| 19 | 2 | a1i | ⊢ ( 𝐹  =  ( √  ↾  𝐴 )  →  𝐴  =  ( 0 [,) +∞ ) ) | 
						
							| 20 | 18 19 | fneq12d | ⊢ ( 𝐹  =  ( √  ↾  𝐴 )  →  ( 𝐹  Fn  𝐴  ↔  ( √  ↾  𝐴 )  Fn  ( 0 [,) +∞ ) ) ) | 
						
							| 21 | 4 20 | ax-mp | ⊢ ( 𝐹  Fn  𝐴  ↔  ( √  ↾  𝐴 )  Fn  ( 0 [,) +∞ ) ) | 
						
							| 22 | 17 21 | mpbir | ⊢ 𝐹  Fn  𝐴 | 
						
							| 23 |  | sinf | ⊢ sin : ℂ ⟶ ℂ | 
						
							| 24 |  | ffn | ⊢ ( sin : ℂ ⟶ ℂ  →  sin  Fn  ℂ ) | 
						
							| 25 | 23 24 | ax-mp | ⊢ sin  Fn  ℂ | 
						
							| 26 |  | fnssres | ⊢ ( ( sin  Fn  ℂ  ∧  ℝ  ⊆  ℂ )  →  ( sin  ↾  ℝ )  Fn  ℝ ) | 
						
							| 27 | 3 | reseq2i | ⊢ ( sin  ↾  𝐵 )  =  ( sin  ↾  ℝ ) | 
						
							| 28 | 27 | fneq1i | ⊢ ( ( sin  ↾  𝐵 )  Fn  ℝ  ↔  ( sin  ↾  ℝ )  Fn  ℝ ) | 
						
							| 29 | 26 28 | sylibr | ⊢ ( ( sin  Fn  ℂ  ∧  ℝ  ⊆  ℂ )  →  ( sin  ↾  𝐵 )  Fn  ℝ ) | 
						
							| 30 | 25 11 29 | mp2an | ⊢ ( sin  ↾  𝐵 )  Fn  ℝ | 
						
							| 31 |  | id | ⊢ ( 𝐺  =  ( sin  ↾  𝐵 )  →  𝐺  =  ( sin  ↾  𝐵 ) ) | 
						
							| 32 | 3 | a1i | ⊢ ( 𝐺  =  ( sin  ↾  𝐵 )  →  𝐵  =  ℝ ) | 
						
							| 33 | 31 32 | fneq12d | ⊢ ( 𝐺  =  ( sin  ↾  𝐵 )  →  ( 𝐺  Fn  𝐵  ↔  ( sin  ↾  𝐵 )  Fn  ℝ ) ) | 
						
							| 34 | 5 33 | ax-mp | ⊢ ( 𝐺  Fn  𝐵  ↔  ( sin  ↾  𝐵 )  Fn  ℝ ) | 
						
							| 35 | 30 34 | mpbir | ⊢ 𝐺  Fn  𝐵 | 
						
							| 36 | 1 | fpar | ⊢ ( ( 𝐹  Fn  𝐴  ∧  𝐺  Fn  𝐵 )  →  𝐻  =  ( 𝑥  ∈  𝐴 ,  𝑦  ∈  𝐵  ↦  〈 ( 𝐹 ‘ 𝑥 ) ,  ( 𝐺 ‘ 𝑦 ) 〉 ) ) | 
						
							| 37 | 22 35 36 | mp2an | ⊢ 𝐻  =  ( 𝑥  ∈  𝐴 ,  𝑦  ∈  𝐵  ↦  〈 ( 𝐹 ‘ 𝑥 ) ,  ( 𝐺 ‘ 𝑦 ) 〉 ) | 
						
							| 38 |  | opex | ⊢ 〈 ( 𝐹 ‘ 𝑥 ) ,  ( 𝐺 ‘ 𝑦 ) 〉  ∈  V | 
						
							| 39 | 37 38 | fnmpoi | ⊢ 𝐻  Fn  ( 𝐴  ×  𝐵 ) | 
						
							| 40 |  | opelxpi | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  〈 𝑋 ,  𝑌 〉  ∈  ( 𝐴  ×  𝐵 ) ) | 
						
							| 41 |  | fvco2 | ⊢ ( ( 𝐻  Fn  ( 𝐴  ×  𝐵 )  ∧  〈 𝑋 ,  𝑌 〉  ∈  ( 𝐴  ×  𝐵 ) )  →  ( (  +   ∘  𝐻 ) ‘ 〈 𝑋 ,  𝑌 〉 )  =  (  +  ‘ ( 𝐻 ‘ 〈 𝑋 ,  𝑌 〉 ) ) ) | 
						
							| 42 | 39 40 41 | sylancr | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( (  +   ∘  𝐻 ) ‘ 〈 𝑋 ,  𝑌 〉 )  =  (  +  ‘ ( 𝐻 ‘ 〈 𝑋 ,  𝑌 〉 ) ) ) | 
						
							| 43 |  | simpl | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  𝑋  ∈  𝐴 ) | 
						
							| 44 |  | simpr | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  𝑌  ∈  𝐵 ) | 
						
							| 45 | 37 43 44 | fvproj | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( 𝐻 ‘ 〈 𝑋 ,  𝑌 〉 )  =  〈 ( 𝐹 ‘ 𝑋 ) ,  ( 𝐺 ‘ 𝑌 ) 〉 ) | 
						
							| 46 | 45 | fveq2d | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  (  +  ‘ ( 𝐻 ‘ 〈 𝑋 ,  𝑌 〉 ) )  =  (  +  ‘ 〈 ( 𝐹 ‘ 𝑋 ) ,  ( 𝐺 ‘ 𝑌 ) 〉 ) ) | 
						
							| 47 |  | df-ov | ⊢ ( ( 𝐹 ‘ 𝑋 )  +  ( 𝐺 ‘ 𝑌 ) )  =  (  +  ‘ 〈 ( 𝐹 ‘ 𝑋 ) ,  ( 𝐺 ‘ 𝑌 ) 〉 ) | 
						
							| 48 | 4 | fveq1i | ⊢ ( 𝐹 ‘ 𝑋 )  =  ( ( √  ↾  𝐴 ) ‘ 𝑋 ) | 
						
							| 49 |  | fvres | ⊢ ( 𝑋  ∈  𝐴  →  ( ( √  ↾  𝐴 ) ‘ 𝑋 )  =  ( √ ‘ 𝑋 ) ) | 
						
							| 50 | 48 49 | eqtrid | ⊢ ( 𝑋  ∈  𝐴  →  ( 𝐹 ‘ 𝑋 )  =  ( √ ‘ 𝑋 ) ) | 
						
							| 51 | 5 | fveq1i | ⊢ ( 𝐺 ‘ 𝑌 )  =  ( ( sin  ↾  𝐵 ) ‘ 𝑌 ) | 
						
							| 52 |  | fvres | ⊢ ( 𝑌  ∈  𝐵  →  ( ( sin  ↾  𝐵 ) ‘ 𝑌 )  =  ( sin ‘ 𝑌 ) ) | 
						
							| 53 | 51 52 | eqtrid | ⊢ ( 𝑌  ∈  𝐵  →  ( 𝐺 ‘ 𝑌 )  =  ( sin ‘ 𝑌 ) ) | 
						
							| 54 | 50 53 | oveqan12d | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( ( 𝐹 ‘ 𝑋 )  +  ( 𝐺 ‘ 𝑌 ) )  =  ( ( √ ‘ 𝑋 )  +  ( sin ‘ 𝑌 ) ) ) | 
						
							| 55 | 47 54 | eqtr3id | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  (  +  ‘ 〈 ( 𝐹 ‘ 𝑋 ) ,  ( 𝐺 ‘ 𝑌 ) 〉 )  =  ( ( √ ‘ 𝑋 )  +  ( sin ‘ 𝑌 ) ) ) | 
						
							| 56 | 42 46 55 | 3eqtrd | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( (  +   ∘  𝐻 ) ‘ 〈 𝑋 ,  𝑌 〉 )  =  ( ( √ ‘ 𝑋 )  +  ( sin ‘ 𝑌 ) ) ) | 
						
							| 57 | 6 56 | eqtrid | ⊢ ( ( 𝑋  ∈  𝐴  ∧  𝑌  ∈  𝐵 )  →  ( 𝑋 (  +   ∘  𝐻 ) 𝑌 )  =  ( ( √ ‘ 𝑋 )  +  ( sin ‘ 𝑌 ) ) ) |