有些填空题、选择题看似虽小,但实质蕴含着丰富的数学知识和思想方法,思维含量并不低.如果加以重视和挖掘,适当的小题大做,则可起到发展思维和提高探究能力,达到练一题、带一类、连一片的目的.因此,小题也大有文章,下面列举一例:例(2014年乌鲁木齐中考题)如图1,半径为3的⊙O内有一点A,OA=3~(1/2),点P在⊙O上.当∠OPA最大时,PA的长等于() Some of the questions to fill in the blank, multiple-choice questions may seem small, but the essence contains a wealth of mathematical knowledge and thinking methods, thinking content is not low.If you pay attention to and dig, appropriate fuss, you can play to develop thinking and improve the ability to explore, Therefore, the topic is also a lot of articles, the following list an example: Example (2014 Urumqi test questions) Figure 1, a radius of 3 ⊙ O a little A, OA = 3 ~ (1/2), the point P in ⊙ O. When ∠ OPA maximum, PA length equal to ()