| Step | Hyp | Ref | Expression | 
						
							| 1 |  | elznn0 |  | 
						
							| 2 |  | cxpmul2 |  | 
						
							| 3 | 2 | 3expia |  | 
						
							| 4 | 3 | ad4ant13 |  | 
						
							| 5 |  | simplll |  | 
						
							| 6 |  | simplr |  | 
						
							| 7 |  | simprr |  | 
						
							| 8 |  | cxpmul2 |  | 
						
							| 9 | 5 6 7 8 | syl3anc |  | 
						
							| 10 | 9 | oveq2d |  | 
						
							| 11 |  | simprl |  | 
						
							| 12 | 11 | recnd |  | 
						
							| 13 | 6 12 | mulneg2d |  | 
						
							| 14 | 13 | negeqd |  | 
						
							| 15 | 6 12 | mulcld |  | 
						
							| 16 | 15 | negnegd |  | 
						
							| 17 | 14 16 | eqtrd |  | 
						
							| 18 | 17 | oveq2d |  | 
						
							| 19 |  | simpllr |  | 
						
							| 20 | 12 | negcld |  | 
						
							| 21 | 6 20 | mulcld |  | 
						
							| 22 |  | cxpneg |  | 
						
							| 23 | 5 19 21 22 | syl3anc |  | 
						
							| 24 | 18 23 | eqtr3d |  | 
						
							| 25 |  | cxpcl |  | 
						
							| 26 | 25 | ad4ant13 |  | 
						
							| 27 |  | expneg2 |  | 
						
							| 28 | 26 12 7 27 | syl3anc |  | 
						
							| 29 | 10 24 28 | 3eqtr4d |  | 
						
							| 30 | 29 | expr |  | 
						
							| 31 | 4 30 | jaod |  | 
						
							| 32 | 31 | expimpd |  | 
						
							| 33 | 1 32 | biimtrid |  | 
						
							| 34 | 33 | impr |  |