如图，△ABC的三条内角平分线相交于点O，过点O作OE⊥BC于E点，

（1）求证：∠BOD=∠COE．

（2）如果AB=17，AC=8，BC=15，利用三角形内心性质及相关知识，求OE长．

根据短文理解，从A、B、C三个选项中选择最佳答案填空。

    Jimmy is an English boy. He wants to have a friend in China. He likes 1 very much. It's relaxing for him. He plays sports 2 his classmates after class. He has five soccer balls, two 3 and one basketball. But he doesn't like tennis. He thinks it's 4. 

Jimmy has a healthy eating 5. He likes fruit and vegetables. 6 are his favorite (最喜欢的) vegetables. He often (经常) has fruit salad 7 dinner. He doesn't eat 8 or ice-cream. He doesn't want to be 9. 

    Do you like him? Do you 10 to be his friend? You can e-mail him at jimmy 012@ yahoo.cn.

a＋b=b＋a