It is known that, as shown in figure a, in △ ABC, AE bisects ∠ BAC (∠ C ＞ b), f is the upper point of AE, and FD ⊥ BC is in D. (1) try to explain: ∠ EFD = 12 (∠ C - ∠ b); (2) when F is on the extension line of AE, as shown in Figure B, other conditions remain unchanged, is the conclusion in (1) still valid? Please give reasons

It is known that, as shown in figure a, in △ ABC, AE bisects ∠ BAC (∠ C ＞ b), f is the upper point of AE, and FD ⊥ BC is in D. (1) try to explain: ∠ EFD = 12 (∠ C - ∠ b); (2) when F is on the extension line of AE, as shown in Figure B, other conditions remain unchanged, is the conclusion in (1) still valid? Please give reasons

If ∵ FD ⊥ EC, ∵ EFD = 90 ° - FEC, ∵ FEC = ∵ B + ∵ BAE, and ∵ AE bisecting ∵ BAC, ∵ BAE = 12 ∵ BAC = 12 (180 ° - B - ∵ C) = 90 ° - 12 (∵ B + ∵ C), then ∵ FEC = ∵ B + 90 ° - 12 (∵ B + ∵ C) = 90 ° + 12 (∵ B - ∵ C), then ∵ EFD = 90 ° - [90 ° + 12 (? B - ?)