O在∠A的平分线上.
证明：过O作OD⊥AB交AB延长线于D,
OE⊥BC于E,OF⊥AC交AC延长线于F,
∵OB为角平分线,∴OD=OE,
∵OC为角平分线,∴OF=OE,
∴OD=OF,
∴在∠A的平分线上.