On BC of triangle ABC, take two points D and e to make BD = CE. Observe the size relationship between ab + AC and AD + AE, and explain the reason

Let's look at a limit case: when D and E are very close, we can consider ad = AE, and D and E are very close to the midpoint F of BC, extend AF to g, so that AF = FG
AG = 2AF = (approximately equal to) AD + AE

AB = AC, BD and CE are the middle lines of triangle ABC, which means BD = CE and angle abd = angle ace

It is proved that △ ADB ≌ △ AEC is OK. Because ∠ a = ∠ a, AC = AB, so 1 / 2Ac = 1 / 2Ab, that is, ad = AE, then △ ADB ≌ △ AEC (corner edge), so BD = CE, ∠ abd = ∠ ace

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