如右图所示，在台阶面上(阴影部分)铺上地毯，

至少需要____平方米的地毯。(各级台阶等高等宽)

已知双曲线$\frac{x^2}{a^2}-\frac{y^2}{b^2}=1$的离心率为2，焦点与椭圆$\frac{x^2}{25}$+$\frac{y^2}{9}$=1 的焦点相同，那么双曲线渐近线方程为____ 

    My wife and I were attending a wedding at St. John's Church. The sound of 1 rang to the heavens as the ceremony continued.

    At the church, I2an old friend, Casper, who happened to be at the 3. Now 73, Casper was a brilliant and 4softball pitched (投球手) back in the Men's Leagues of Philadelphia in the mid-60s. I did not5 the now silver-haired fellow until my brother-in-law John mentioned his name to me! After a very pleasant6 Casper asked if I remembered a letter of7I had written to him back in 1964. It appeared Casper fell on hard times, as professional pitchers 8 do, and he wasn't pitching too well for a period of time. I did not9the letter, but he said, “Yes, I still have it, and I read it anytime 10aren't going too well.” He said that he had read the letter many times, and the situation always seemed to improve. I was 11and speechless!

    He continued, “You don't remember?” I said, “Sadly, no, I don't.” but I did ask if I could have a(n)12of the letter. He said he would email it to me. After the 13, we met on the steps of the church. Casper came up to me and 14 the letter. He lived a block from the 15and had run home to get it. The envelope was 16 and turned yellow, and so was the letter inside. That letter had to be nearly 50 years old.

In17term, the letter read:

    “These hard times are18! Keep your enthusiasm for the19Never quit and you will be back on top again 20Hang on there!”