Database REAL AND COMPLEX NUMBERS Real and complex numbers - basic operations Reciprocals mulne0bbd  
				
		 
		
			
		 
		Description:   A factor of a nonzero complex number is nonzero.  Partial converse of
       mulne0d  and consequence of mulne0bd  .  (Contributed by David Moews , 28-Feb-2017) 
		
			
				
					Ref 
					Expression 
				 
					
						Hypotheses 
						mulne0bad.1 ⊢  ( 𝜑   →  𝐴   ∈  ℂ )  
					
						mulne0bad.2 ⊢  ( 𝜑   →  𝐵   ∈  ℂ )  
					
						mulne0bad.3 ⊢  ( 𝜑   →  ( 𝐴   ·  𝐵  )  ≠  0 )  
				
					Assertion 
					mulne0bbd ⊢   ( 𝜑   →  𝐵   ≠  0 )  
			
		 
		
				Proof 
				
					
						Step 
						Hyp 
						Ref 
						Expression 
					 
						
							1 
								
							 
							mulne0bad.1 ⊢  ( 𝜑   →  𝐴   ∈  ℂ )  
						
							2 
								
							 
							mulne0bad.2 ⊢  ( 𝜑   →  𝐵   ∈  ℂ )  
						
							3 
								
							 
							mulne0bad.3 ⊢  ( 𝜑   →  ( 𝐴   ·  𝐵  )  ≠  0 )  
						
							4 
								1  2 
							 
							mulne0bd ⊢  ( 𝜑   →  ( ( 𝐴   ≠  0  ∧  𝐵   ≠  0 )  ↔  ( 𝐴   ·  𝐵  )  ≠  0 ) )  
						
							5 
								3  4 
							 
							mpbird ⊢  ( 𝜑   →  ( 𝐴   ≠  0  ∧  𝐵   ≠  0 ) )  
						
							6 
								5 
							 
							simprd ⊢  ( 𝜑   →  𝐵   ≠  0 )