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英語 中学生

問4の並び替えはどのように考えて解けばいいのですか?

3 次は、高校生のHayato (男性) が書いた文章です。 これを読んで, 間 1~ 問6に答えなさい。 *印の ついている語句には、本文のあとに〔注〕があります。(34点) I love bicycles. I've been using my bicycle since I was a junior high school student. One morning, however, I got scared on my way to school. A car passed me really fast. It almost touched my bicycle. There are only a few *bicycle lanes in my town, and I think some of those lanes are too narrow for a bicycle to use safely. I wanted to make our streets safer for cyclists, and then I read about "Copenhagen, Denmark in a bicycle "magazine. It's Aas one of the most *bicycle-friendly cities in the world. I learned more about the city on the Internet and thought it's really a wonderful city for cyclists. I'd like to write about it. In Denmark. 90% of the people have a bicycle, and in Copenhagen, 49% of the workers and students go to work or school by bicycle (27 % go by car, 18% by bus or train, and 6% on foot). Many streets in the city have bicycle lanes and bicycle traffic lights, and there is even a bicycle bridge named "The Bicycle "Snake." I was "envious of the cyclists in Copenhagen because the city is bicycle-friendly in every way. You can ride a bicycle at 20 km/h without B at red lights even when the traffic is busy, and you can bring your bicycle on trains and buses. In the 2019 ranking of "Bicycle-friendly Cities," Copenhagen was No. 1 and Tokyo was No. 16. ② A lot of people were using cars in Copenhagen, too, but around 1980, the city started making better roads and rules for bicycles, and the number of bicycle users started increasing. Around 2017, the number of bicycle users in Copenhagen became almost the same as the number of car users. I was also surprised to see that the number of bicycle accidents in Copenhagen was "lower than in other large cities. I think it's because the roads (cyclists for safe/follow/ and/ are cyclists the traffic rules. In many Japanese road safety classes, children are taught that roads are dangerous and sometimes shown shocking scenes of traffic accidents, and they learn that they must follow traffic rules when they ride a bicycle. But in Denmark. children play games in their classes. They can have fun when they learn traffic rules. Now there is a movement in Japan that gives children road safety classes in this way. Bicycles are cheaper than cars and healthier. They're also friendlier to the environment. The United Nations expects that about 70% of the people in the world will live in big cities by 2050. Such a large number of people will cause some problems, and more traffic is one of them. Copenhagen is a very good role model for Sustainable cities and communities" which is one of the U.N.'s "Sustainable Development Goals. I think Copenhagen's ideas to increase the number of bicycle users are wonderful because people there don't have to stop doing anything. They choose bicycles because the city is designed in a way that using a bicycle is more convenient than using a car, bus. or train. However, after the number of bicycle users increased, more parking spaces are needed there. (3 To make a bicycle-friendly city, just making more bicycle lanes isn't enough. We must think about the future of our cities. Denmark has made a lot of great plans and has more exciting plans for the future. For example, it's going to build a "bicycle" "superhighway" between cities and other areas by around 2045. I definitely want to ride a bicycle on it some day! 〔注〕 be cared おびえて こわがって bicycle lane 自転車専用の車線. レーン cyclist ...... 自転車乗りの人、サイクリスト pass…………〜を追いこす。 通り過ぎる narrow ・・・・・・幅が狭い Copenhagen コペンハーゲン (Denmark 「デンマーク」の首都) magazine 雑誌 on foot... 徒歩で bicycle-friendly... 自転車にやさしい traffic light...信号 (traffic は 「交通 (量)」)

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数学 高校生

この問題なんですが、2枚目の動画授業と似ている問題だったので参考に解いていたのですが、一枚目だと2log2anをbnとおいている辺りから進めません!2枚目のやり方の方が自分にはあっているなと感じたのでそっちのやり方で進めたいのですが、一枚目の問題になるとできなくなってしまい... 続きを読む

3 漸化式と数学的帰納法 (77) B1 題 B1.35 漸化式 antipan" たぶん次数相型 a=2, +1=4am で定義される数列{an} の一般項 am を求めよ. **** え方 漸化式がα+1 や ami などの累乗の場合や, に √ がついている場合, 10月のよう な積の場合は,両辺の対数をとるとうまくいくことが多い。 ここでは,a の係数4(=22) に着目して, 底が2である対数を両辺にとると, log2an+1=log2(4a)=log24+logza3 より 210g2a+1=2+310gzan ここで, log2am=b" とおくと, 26+1=36+2となり、例題 B1.32 の形の漸化式となる. a=2>0, an+1=4amより, すべての自然数nに対して an>0 an+12=4am について 底2で両辺の対数をとると, logzan+1=10g24a73 m 210gz4+1=log24+310gzan より oga=b とおくと, 210gza+1=310gza,+2 26+1=36+2 したがって,bn+1= 本来マイナス 3 20m+1 より、これを変形すると 3 に ここで, b1+2=10gza1+2=10g22+2=3 下の注〉 参照 漸化式の形と初値 すべての自然につい amであると分か bn+1+2=2(b+2) ……① 3 ①とb+2=3 より, 数列{b,+2} は,初項 3.公比の 特性方程式 3 α=24+1を解くと α-2 21egant 3/ 等比数列だから,一般項は, bn+2=3 3 3" すなわち, bn b-3-2-3-20 2= -x-2 よっち bn=10gzan=- 3"-2" 2n-1 3"-2" X=-2 より an-2 2-1 Ocus 漸化式 an+1=pan" は両辺の対数をとる -注> 「α」=2, am+12=4a73 のとき, すべての自然数について am>0」について a2=4a=4.23 仮に a2= -4 bu= 3" 244-2 よって, 20 3" 2 2.244 2 34-2" 21 (1) 34-2-244 21-7 える (

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