Metamath Proof Explorer
		
		
		
		Description:  The logarithm isn't 0 if its argument isn't 0 or 1, deduction form.
       (Contributed by SN, 25-Apr-2025)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypotheses | logccne0d.a | ⊢ ( 𝜑  →  𝐴  ∈  ℂ ) | 
					
						|  |  | logccne0d.0 | ⊢ ( 𝜑  →  𝐴  ≠  0 ) | 
					
						|  |  | logccne0d.1 | ⊢ ( 𝜑  →  𝐴  ≠  1 ) | 
				
					|  | Assertion | logccne0d | ⊢  ( 𝜑  →  ( log ‘ 𝐴 )  ≠  0 ) | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | logccne0d.a | ⊢ ( 𝜑  →  𝐴  ∈  ℂ ) | 
						
							| 2 |  | logccne0d.0 | ⊢ ( 𝜑  →  𝐴  ≠  0 ) | 
						
							| 3 |  | logccne0d.1 | ⊢ ( 𝜑  →  𝐴  ≠  1 ) | 
						
							| 4 |  | logccne0 | ⊢ ( ( 𝐴  ∈  ℂ  ∧  𝐴  ≠  0  ∧  𝐴  ≠  1 )  →  ( log ‘ 𝐴 )  ≠  0 ) | 
						
							| 5 | 1 2 3 4 | syl3anc | ⊢ ( 𝜑  →  ( log ‘ 𝐴 )  ≠  0 ) |