【解释一下过程】双曲线x^2/9-y^2/16=1的两个焦点为F1,F2,

如果 P(x, y) (x/3)^2 - (y/4)^2 =1 -> 16x^2 - 9y^2 = 9*16 --(1) 向量PF1·向量PF2=0 -> ( x+5, y-0) ( x-5 , y-0 ) =0 -> x^2 - 5^2 + y^2 =0 ---(2) (1), (2) 16( 25 - y^2 ) - 9 y^2 = 9*16 16*25 - 25y^2 = 16 *9 16(25-9) = 25 y^2 16^2 = 5^2 y^2 y^2 = (16/5 )^2 因此 点P到x轴的距离 -> | y 坐标 | 【答案是：16/5】