| Step | Hyp | Ref | Expression | 
						
							| 1 |  | tngval.t |  | 
						
							| 2 |  | tngval.m |  | 
						
							| 3 |  | tngval.d |  | 
						
							| 4 |  | tngval.j |  | 
						
							| 5 |  | elex |  | 
						
							| 6 |  | elex |  | 
						
							| 7 |  | simpl |  | 
						
							| 8 |  | simpr |  | 
						
							| 9 | 7 | fveq2d |  | 
						
							| 10 | 9 2 | eqtr4di |  | 
						
							| 11 | 8 10 | coeq12d |  | 
						
							| 12 | 11 3 | eqtr4di |  | 
						
							| 13 | 12 | opeq2d |  | 
						
							| 14 | 7 13 | oveq12d |  | 
						
							| 15 | 12 | fveq2d |  | 
						
							| 16 | 15 4 | eqtr4di |  | 
						
							| 17 | 16 | opeq2d |  | 
						
							| 18 | 14 17 | oveq12d |  | 
						
							| 19 |  | df-tng |  | 
						
							| 20 |  | ovex |  | 
						
							| 21 | 18 19 20 | ovmpoa |  | 
						
							| 22 | 5 6 21 | syl2an |  | 
						
							| 23 | 1 22 | eqtrid |  |