题目

如图,一次函数的图象与反比例(k为常数,且k≠0)的图象交于A(1,a),B两点.                                                                    (1)求反比例函数的表达式及点B的坐标;                                                                 (2)在轴上找一点P,使PA+PB的值最小, 求满足条件的点P的坐标及△PAB的面积. 答案:(1) 反比例函数的表达式为,                                                                          。                                    (2) 如答图所示,把B点关于x轴对称,得到,                                     连接交x轴于点,连接,易得直线:,令,得,∴,即满足条件的P的坐标为,                                                                          设交x轴于点C,则,                                                                            ∴,                                                              即    
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