| Step | Hyp | Ref | Expression | 
						
							| 1 |  | isosctrlem3.1 |  | 
						
							| 2 |  | simp1l |  | 
						
							| 3 |  | simp21 |  | 
						
							| 4 |  | simp1r |  | 
						
							| 5 | 2 4 | subcld |  | 
						
							| 6 |  | simp23 |  | 
						
							| 7 | 2 4 6 | subne0d |  | 
						
							| 8 | 1 | angneg |  | 
						
							| 9 | 2 3 5 7 8 | syl22anc |  | 
						
							| 10 | 2 4 | negsubdi2d |  | 
						
							| 11 | 10 | oveq2d |  | 
						
							| 12 |  | 1cnd |  | 
						
							| 13 |  | ax-1ne0 |  | 
						
							| 14 | 13 | a1i |  | 
						
							| 15 | 4 2 3 | divcld |  | 
						
							| 16 | 12 15 | subcld |  | 
						
							| 17 | 6 | necomd |  | 
						
							| 18 | 4 2 3 17 | divne1d |  | 
						
							| 19 | 18 | necomd |  | 
						
							| 20 | 12 15 19 | subne0d |  | 
						
							| 21 | 1 12 14 16 20 | angvald |  | 
						
							| 22 | 16 | div1d |  | 
						
							| 23 | 22 | fveq2d |  | 
						
							| 24 | 23 | fveq2d |  | 
						
							| 25 | 4 2 3 | absdivd |  | 
						
							| 26 |  | simp3 |  | 
						
							| 27 | 26 | eqcomd |  | 
						
							| 28 | 27 | oveq1d |  | 
						
							| 29 | 2 | abscld |  | 
						
							| 30 | 29 | recnd |  | 
						
							| 31 | 2 3 | absne0d |  | 
						
							| 32 | 30 31 | dividd |  | 
						
							| 33 | 25 28 32 | 3eqtrd |  | 
						
							| 34 | 19 | neneqd |  | 
						
							| 35 |  | isosctrlem2 |  | 
						
							| 36 | 15 33 34 35 | syl3anc |  | 
						
							| 37 | 15 | negcld |  | 
						
							| 38 |  | simp22 |  | 
						
							| 39 | 4 2 38 3 | divne0d |  | 
						
							| 40 | 15 39 | negne0d |  | 
						
							| 41 | 1 16 20 37 40 | angvald |  | 
						
							| 42 | 36 41 | eqtr4d |  | 
						
							| 43 | 21 24 42 | 3eqtrd |  | 
						
							| 44 | 2 | mulridd |  | 
						
							| 45 | 2 12 15 | subdid |  | 
						
							| 46 | 4 2 3 | divcan2d |  | 
						
							| 47 | 44 46 | oveq12d |  | 
						
							| 48 | 45 47 | eqtrd |  | 
						
							| 49 | 44 48 | oveq12d |  | 
						
							| 50 | 1 | angcan |  | 
						
							| 51 | 12 14 16 20 2 3 50 | syl222anc |  | 
						
							| 52 | 49 51 | eqtr3d |  | 
						
							| 53 | 2 15 | mulneg2d |  | 
						
							| 54 | 46 | negeqd |  | 
						
							| 55 | 53 54 | eqtrd |  | 
						
							| 56 | 48 55 | oveq12d |  | 
						
							| 57 | 1 | angcan |  | 
						
							| 58 | 16 20 37 40 2 3 57 | syl222anc |  | 
						
							| 59 | 56 58 | eqtr3d |  | 
						
							| 60 | 43 52 59 | 3eqtr4d |  | 
						
							| 61 | 9 11 60 | 3eqtr3d |  |