观察下列各式及其验证过程：

$2\sqrt{\frac{2}{3}}$=$\sqrt{2+\frac{2}{3}}$

验证：$2\sqrt{\frac{2}{3}}$=$\sqrt{\frac{2^3}{3}}$=$\sqrt{\frac{\left(2^3-2\right)+2}{2^2-1}}$=$\sqrt{\frac{2\left(2^2-1\right)+2}{2^2-1}}$=$\sqrt{2+\frac{2}{3}}$$·3\sqrt{\frac{3}{8}}$=$\sqrt{3+\frac{3}{8}}$

验证：$3\sqrt{\frac{3}{8}}$=$\sqrt{\frac{3^3}{8}}$=$\sqrt{\frac{\left(3^{3}3\right)+3}{3^{2}1}}$=$\sqrt{\frac{3\left(3^{2}1\right)+3}{3^{2}1}}$=$\sqrt{3+\frac{3}{8}}$

（1）按照上述两个等式及其验证过程的基本思路，猜想$5\sqrt{\frac{5}{24}}$的变形结果并进行验证；

（2）针对上述各式反应的规律，写出用n（n为任意自然数，且n≥2）表示的等式，并说明它成立．

    My mother is a teacher. On weekdays, she gives lessons at school and on Saturdays she works in clubs. On Sundays, she is still busy.

On Sunday morning, mum gets up at six. She cooks breakfast for us first. And then it's time for cleaning. After that, she has breakfast with father and me. At 9, she goes to buy food for lunch in the supermarket. She can have a short rest after lunch. In the afternoon, mum doesn't go out. She helps me with my lessons. She does some reading, too.

    Mother watches TV at about 7 when she finishes (完成) the housework. But at that time she is always tired and falls asleep (睡着) in the sofa sometimes.

我国年降水量分布的总趋势是（　　）