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Mathematics Senior High

数列 チャートからの質問です 解答のゆえに以降でやっていることについて、理解があっているか教えていただきたいです。 まずa1=b1が成り立つのは明らか 次にalとbmが等しいと仮定し、二項関係が分かれば数列を定められるから、(予想から)bmの項を順に進めていって次に等... Read More

534 重要 例題 100 等差数列と等比数列の共通項 数列{an}, {bn}の一般項を α=3n-1,bn=2" とする。 数列{bn} の項のうち、数 列{an}の項でもあるものを小さい方から並べて数列{C} を作るとき, 数列{C} の一般項を求めよ。 指針 2つの等差数列の共通な項の問題 (例題93) と同じように,まず, 4=bm として、lとmの 関係を調べるが,それだけでは {cn}の一般項を求めることができない。 そこで,数列{an}, {bn} の項を書き出してみると,次のようになる。 {an}:2,5,8, 11, 14, 17, 20, 23, 26, 29, 32, ...... {bn}:2,4,8, 16, 32, ・・ ゆえに a=b, Ca=by, cy=b, となっていることから,数列{bn} を基準として, bm+1 が数列{4) さらにの頃となるかどうか, bm+2が数列{an}の項となるかどうか ….………. を順に調べ、規則性を 見つける。・・・・・・・ 解答 α1=2, b=2であるから C1=2 数列{an}の第1項が数列{bn}の第m項に等しいとすると 3l-1=2" bm+1=2m+1=27.2=(3L-1)・2 重要 93 基本 99 =3-21-2 自よって, bm+1 は数列{an}の項ではない。 ①から bm+2=26m+1=3.41-4 =3(4-1)-1 ] ゆえに, bm+2 は数列{an}の項である。 したがって {C}:61,63,65, 数列{cn}は公比22の等比数列で, C1 = 2 であるから cn=2.(22) "1=22n-1 22"=4"=1"≡1(mod3) [2] m=2n-1(nは自然数) とすると an=30-1 <30-1 の形にならない。 4n cm=2 などと答えても 検討 合同式(チャート式基礎からの数学A 参照) を用いた解答 3n-1=-1=2 (mod3) であるから 22 (mod3) となるmについて考える。 [1] =n(nは自然数) とすると 22n-122(n-1).2=4n-1.2=1"-1.2=2 (mod3) [1], [2] より m=2n-1 (nは自然数) のとき2” が数列{C}の頃になるから Cn=62n-1=22n-1 数列{an},{bn}の一般項をan=15n-2, bn=7.27-1とする。 数列{bn} の項 コち, 数列{an}の項でもあるものを小さい方から並べて数列{C} を作るとき, { cm}の一般項を求めよ。

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English Senior High

時間を意識して解きたいのですが、目安時間が分からないです。偏差値60を近いうちの目標にしている者です。 これは400 word 神奈川大学の問題です。記述が4問、選択が2問という点も考慮して目安時間を教えて頂けると嬉しいです。お願いします。

400 words/ Unit 7-Language - 1 All over the world, there are hundreds of languages that will soon disappear, some of them spoken only by a single person. "Languages are now dying at a faster rate than ever before," said David Harrison, a professor of language studies. Harrison has traveled the world to interview the last speakers of languages that are in danger of disappearing. 5 2 Bolivia* has a far greater variety of languages than all the countries of Europe combined. but they are increasingly threatened by dominant languages such as Spanish. In Bolivia, Harrison met with people who have used certain plants as medicine since the time of the Inca Empire*. Besides a common local language, they also maintain a secret language to name thousands of plants used as medicines, some unknown to science. 10 3 (1) When a language is lost, centuries of human thinking about such things as animals and plants may be lost with it. Eighty percent of existing species have not yet been discovered by science. However, (2) this does not mean that they are unknown to humans, because the people who live close to them know those species (3)intimately. They often have more detailed ways of classifying them than science does. 15 4 In Micronesia*, there are a handful of people who can sail across thousands of kilometers of ocean without any modern instruments of navigation. Their languages have a special set of terms for these skills. If their languages are lost, (4)their navigational skills will be lost, too. 5 Children are often the ones who decide to abandon a native tongue. "(5)It's actually the children, not the parents, who have the power to make the decision that will affect the 20 community and the future of their language," Harrison said. He was encouraged by an experience he had in Australia, when he watched a woman in her eighties teaching her language to schoolchildren. She was one of only three speakers of an aboriginal* language. The lesson was about plants which are used as medicine in aboriginal culture. 6 "The children had chosen to learn the language - no one forced them. When we 25 asked why they were learning it, they said, 'This is a dying language. We need to learn it.' The woman waved the plants in front of the children and said something in her language about them, which they repeated. It was an amazing thing to watch her communicate that knowledge to the children. That inspired us greatly." quor 左の英文を読み、下の各問いに答えなさい。 ごとの SPONS 1. 下線部 (1) を日本語に直しなさい。 ただし, it が何を指すのかわかるようにすること。 下線部 (3) の意味として最も適切なものを選びなさい。 [3. with a deep knowledge 3 in one's private life 2. 下線部 (2) を日本語に直しなさい。 ただし, this が何を指すのかわかるようにすること。 5. 下線部 (5) を日本語に直しなさい。 3050 in a friendly manner 4 in secret 4. 下線部 (4) はどのような技術か, 日本語で説明しなさい。 2x030 D 6. 本文の内容に合うものを2つ選びなさい。 Harrison has traveled even in dangerous places to interview the last speakers of disappearing languages. The total number of languages in Bolivia alone is larger than that of all the languages used in Europe. From a scientific point of view, the medical plants used in Bolivia have little value. An old woman in Australia was teaching her language to children, but they did not want to learn it. The old woman was teaching not only her language, but also her knowledge about medical plants in her aboriginal culture. istory Culture anguage ociety Health Science Nature

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