原题:如图,在△ABC中,∠ABC=90°,AB=3~(1/2),BC=1,P为△ABC内一点,∠BPC=90°.(I)若PB=1/2,求PA;(II)若∠APB=150°,求tan∠PBA.一、试题评价本题从给出的形式上区别于近几年的考题模型,不再是大家熟悉的以边角混合形式给出的解三角形或是研究三角函数的图像及性质问题,因此导致很多学生觉得无从下手,而实际上此题恰恰是回归了课本中的解三角形 ABC: ∠ABC = 90 °, AB = 3 ~ (1/2), BC = 1, P is a point in △ ABC, ∠BPC = 90 ° (I) If PB = 1/2, find PA; (II) If ∠APB = 150 °, find tan∠PBA. First, the test questions from the given form of the test is different from the model in recent years, is no longer familiar with the edge Angular mixture of given solution triangle or study trigonometric function of the image and nature of the problem, resulting in many students feel unable to start, but in fact this problem is precisely regression textbook solution triangle