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数学 高校生

数B なぜ四角のようになるのか分かりません 教えてください!!

(2) 第1 CHART OLUTION 和を求めよ。 2-1-1 2-1 [類 京都産大] 群数列の基本 第群の最初の項や数 に注目...... 例題のように,群に分けられた数列 を群数列という。 (1) 第4群の末頃までの項の総数を N とすると, 第5群の初めの数は、自然数の 列の第 (N+1) 項である。 また, 自然数の列の第1項の数はとなる (2) 連続する自然数の和であるから公差1の等差数列の和で,あとは初項と 数がわかればよい。 初項は (1) と同様にして求まる。 項数は問題文から すぐ にわかる。 区切りを入れる と分け方の規則 がみえてくる もとの数列 群数列 FE 第4群の末項までの項の総数は 1+2+22+2°=15 第5群の末頃までの項の総数は 1+2+2²+2³+2¹=31 よって,第5群の初めの数は 16,終わりの数は31 2) n≧2のとき,第 (n-1) 群の末項までの項の総数は n-1 Σ2²-1= -=2n-1-1 k=1 (1+x)k 20001 ゆえに,第n群の初めの数は ( 2 -1-1)+1 すなわち 27-1 BANDITU 重要 98 区切りをとると もとの数列の規 則がみえてくる - n-1 Σ2-1は,初項1,公比 k=1 2の等比数列の初項か (n-1)項までの和。 これは n=1のときにも成り立つ。 別解 第n群の終わりの数 よって,第n群に含まれる数の総和は,初項が2" -1, 公差がは2"-1 であるから、和は 項数が 2-1 の等差数列の和となるから、求める和は 11.2"-'{2"-' +(2"-1)} 2 1/1/20 ・2"-1(2.2"-1+(2″-1-1)・1}=2"-2(3.2"-1-1) =2"-2(3-2-¹-1) TRACTICE ... 97 ② 正の奇数の列を次のように, 第n群が (2n-1) 個の奇数を含むように分ける。 1/3, 5, 7 9, 11, 13, 15, 17|19, 21, 23, 25, 27, 29, 31/...... 80 3章 12

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英語 高校生

問2についてです。 解説の黄色の線が引いてあるところが理解できません。

次の英文を読んで, (1) Considerable attention has been paid to the size or relative size of the human brain. The first point of interest is that the ratio of brain weight to body is at a maximum at birth and decreases with age, reaching a fairly steady level by maturity. In other 5 words, newborn babies have very large brains, relatively speaking, weighing some 300 grams. This is roughly the size of the brain Children and their brains continue of an adult male chimpanzee. to grow for many years, gradually increasing their ability to learn and remember. There have been suggestions that the growth of 10 the brains of children is not steady, but occurs suddenly, each period of rapid growth ( 2 ) associated with a particularly important developmental or intellectual stage. These stages could be the ability to reason abstractly, to talk, or even to do arithmetic. The idea of sudden brain growth is still around, but 15 has not attracted much enthusiasm. Some research has shown differences in the relative sizes of the brains of males and females of the same age, but so far no great differences have been found between people of the same age but of different ethnic groups. Obviously the brain of a 20 small Japanese teenager is very much smaller than that of a giant Russian boy. But when brain size is adjusted for size or weight of the body, there ( 3 ) great advantage for either with respect to intelligence. Moreover, in measuring intelligence one has, of course, to take into account the effects of education 25 and cultural background. (4) Individual brain sizes, particularly of famous people, have also 10

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英語 中学生

(2)Planting Aの中でPlantingにあたるものを教えてほしいです

次の内容が同じ 【A】 【B】 の英文を読み、 【B】 の空所に適語を補いなさい。 (5) 【思考・判断・表現 】 [A] After that she visited many countries and wrote about her experiences in them. In her travels, she was attracted to Japan and the cherry blossoms there. She especially loved to see their reflection in water. She dreamt of creating a scene like that along the Potomac River. After she came back from her first trip to Japan, she wrote letters and proposed the idea to the people in charge of national parks. However, they wouldn't accept her idea because cherry trees were from a foreign country. She did not give up, though. She was determined to plant the most beautiful trees in the world. Those are Japan's cherry trees which have beautiful blossoms." [B] After that she traveled to many countries and wrote about her experiences in them X )( X ) the cherry blossom: In her travels, she visited Japan and 1)( She especially loved to see the reflection of the cherry blossoms in water. 2)( trees along the Potomac River in Washington, D.C. became her dream. cher After she 3)( ) from her first trip to Japan, she wrote letters to people in char ) of national parks. They did not want trees from a different country, so they 4)( idea. She did not give up, though. She thought, "If you are going to plant trees, should plant the most beautiful trees in the world. Those are Japan's cherry tr 5) ( ) their beautiful blossoms." 2

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