函数f（x）=x²﹣2x﹣3，定义数列{ x_n}如下：x₁=2，x_n+1是过两点P（4，5），Q_n（ x_n，f（x_n））的直线PQ_n与x轴交点的横坐标．

A

    Skin­diving is a new sport today. This sport takes you into a wonderful new world. It is like a visit to the moon. When you are under the water, it is easy for you to climb big rocks, because you are no longer heavy.

    Here, under the water, everything is blue and green. During the day, there is plenty of light. When fish swim nearby, you can catch them with your hands.

When you have tanks of oxygen on your back, you can stay in deep water for a long time. But you must be careful when you dive in deep water.

    To catch fish is one of the most interesting parts of this sport.

    What's more, there are more uses for skin­diving. You can clean ships without taking them out of water. You can get many things from the deep sea.

    Now you see that skin­diving is both useful and interesting.

近年来，伴随着航班晚点频发，乘客与航空公司纠纷不断， “空怒族”随之诞生，他们发难机场人员、拦飞机、罢乘、拒绝下飞机……
请运用所学知识谈谈对“空怒族”行为的认识。