题目如图,PAPAPA,PBPBPB切⊙O\odot O⊙O于AAA,BBB两点,CDCDCD切⊙O\odot O⊙O于点EEE,交PAPAPA,PBPBPB于CCC,DDD,若⊙O\odot O⊙O的半径为rrr,△PCD\triangle PCD△PCD的周长等于3r3r3r,则tan12∠APB\tan \frac{1}{2}\angle APBtan21∠APB的值是____.知识点:切线长定理章节:图形的性质 / 圆