如图,△ABC中,AB=AC,∠BAC=54°,∠BAC的平分线与AB的垂直平分线交于点O,将∠C沿EF(E在BC上,F在AC上)折叠,点C与点O恰好重合,则∠OEC为 度.
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(-1)2n =______;(-1)2n+1 =________;
(-0.1)3=_______;
(-5) 2 =________;
(-3)3 =__________;