Theorem anbi2d

Description: Deduction adding a left conjunct to both sides of a logical equivalence. (Contributed by NM, 11-May-1993) (Proof shortened by Wolf Lammen, 16-Nov-2013)

	Ref	Expression
Hypothesis	anbid.1	⊢ ( 𝜑 → ( 𝜓 ↔ 𝜒 ) )
Assertion	anbi2d	⊢ ( 𝜑 → ( ( 𝜃 ∧ 𝜓 ) ↔ ( 𝜃 ∧ 𝜒 ) ) )

Proof

Step	Hyp	Ref	Expression
1		anbid.1	⊢ ( 𝜑 → ( 𝜓 ↔ 𝜒 ) )
2	1	a1d	⊢ ( 𝜑 → ( 𝜃 → ( 𝜓 ↔ 𝜒 ) ) )
3	2	pm5.32d	⊢ ( 𝜑 → ( ( 𝜃 ∧ 𝜓 ) ↔ ( 𝜃 ∧ 𝜒 ) ) )