△ABC中,AE平分∠BAC,∠C>∠B.(1)①在图1中,若AD⊥BC于D,∠C=60°、∠B=40°则∠DAE=______;②在图2中,若点P是AE上的一动点,过点P作PG⊥BC于G,则∠EPG与∠C、∠B之间的相等关系是∠EPG=12∠C-12∠B∠EPG=12∠C-12∠B;(2)若点P是AE延长线上一点,过点P作PG⊥BC于G,则∠EPG与∠C、∠B之间有何相等关系?画出图并证明你的结论.
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