Description: Equality deduction for function value. (Contributed by BJ, 30-Aug-2022)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | fveqeq2d.1 | ⊢ ( 𝜑 → 𝐴 = 𝐵 ) | |
| Assertion | fveqeq2d | ⊢ ( 𝜑 → ( ( 𝐹 ‘ 𝐴 ) = 𝐶 ↔ ( 𝐹 ‘ 𝐵 ) = 𝐶 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | fveqeq2d.1 | ⊢ ( 𝜑 → 𝐴 = 𝐵 ) | |
| 2 | 1 | fveq2d | ⊢ ( 𝜑 → ( 𝐹 ‘ 𝐴 ) = ( 𝐹 ‘ 𝐵 ) ) |
| 3 | 2 | eqeq1d | ⊢ ( 𝜑 → ( ( 𝐹 ‘ 𝐴 ) = 𝐶 ↔ ( 𝐹 ‘ 𝐵 ) = 𝐶 ) ) |