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数学 高校生

なぜOH=sa+tbとしてるんですか?

p 基本 例題 25 垂心の位置ベクトル 平面上に△OAB があり、OA=5,OB=6, AB=7 とする。 また, △OABの垂 00000 心をHとする。 (1) COS ∠AOB を求めよ。 (2) OA= a, OB = とするとき, OH を a, 1 を用いて表せ。 指針 三角形の垂心とは, 三角形の各頂点から対辺またはその延長に下ろした垂線の交点であり, 解答 △OABの垂心Hに対して, OA⊥BH, OBIAH, ABIOH が成り立つ。 そこで, OA⊥BH といった図形の条件をベクトルの条件に 直して解く。 (2) では OH = sa+t とし, OA・BH=0, OB・AH=0 の2つの条件から,s,tの値を求める。 (1) 余弦定理から EDU COS ∠AOB= OA⊥BH より OA・BH=0 である から よって ゆえに 25s+6(t-1)=0 すなわち 25s+6t=6 ① また, OB ⊥AHよりOB・AH = 0 であるから {(s-1)a+t}=0 (s-1)ã·6+t|b²=0 したがって (2) (1) 5 à·b=|ā||5|cos <AOB=5.6.-= -=6 △OAB は直角三角形でないから,垂心Hは2点A,Bと 一致することはない。 F 21-9 Hは垂心であるから OA⊥BH, OB⊥AH OH = sa + to (s,t は実数)とする。 A+8A CHORUSS 0 52 +62-72 2・5・6 S= a•{sa+(t-1)}=0 tsasaH slal²+(t-1)ã·b=0C=100 よって ゆえに 6(s-1)+36t=0 すなわち s+6t=1 19 ① ② から 1)-(2*4 144 5 24' OH= 12 1 60 5 t= A 5 → 2ä+ 196 a+ 24 144 = p.400 基本事項 ⑤ 631 B ------ A stronas 重要 28 [参考] AB=18- =161²-26-a+la1² H |AB|=7, |a|=5, ||=6で あるから 72=62-2 ・a +5² よって 1=6 18-TA ①垂直→ (内積) = 0 BH = OH-OB O |a| =5, a-6=6 ①垂直→ (内積) = 0 ■AH=OH-OA A HA①-②から 24s=5 HA& 2a-6-6, 161=63 3x+u+= B 421 4 位置ベクトル、ベクトルと図形 X

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英語 高校生

問題を解いたのですが答えが分かりません😭教えてください🙏

テーマ 資源・エネルギー 10 文法項目 動名詞(いろいろな形/動名詞と不定詞) UNIT 6 Reading Track 29-30 HUNDR パンダのふんの研究が、いつの日か環境問題の解決に寄与するかもしれません。 In June, 2016, a baby *giant panda, Tian Bao, was born at a zoo in Belgium. It became big news because the birth of a baby panda is an *extremely Actually, that of Tian Bao was only the sixth in Europe in the last 20 years. While its population is slowly increasing, the giant panda remains one of the rarest animals 5 in the world. Therefore, scientists have been doing research on how pandas have babies. rare event. So, you may think the scientists working at the Belgium zoo *accomplished the goal of their research. But they have another goal; apart from having done that research, they've been studying panda *poo. Why are they doing that? G Som pluoda Dol Tian Bao's mother Hao Hao and its father Xing Hui live in the same zoo as their baby does. While they enjoy sitting in the sun and eating bamboo, iedario ew dinga 2.5T (s) the scientist team collects their poo. By studying the poo, the team is aiming to understand how pandas can digest bamboo. Note 30 In fact, bamboo is receiving a lot of attention in biofuel research these days. 15 It's among the fastest-growing plants on earth, and yet needs the least care. So the in hewa plant can become a good source of *renewable energy. But because bamboo is very tough and hard to *degrade, today's method for making a biofuel from bamboo costs a lot. *Technically, pandas are meat-eating animals, but over the years the food they eat 20 has changed to almost only bamboo. The scientists are trying to find the *microbes that help a panda digest about 10kg of bamboo a day. By using these microbes, they will be able to discover an easy and cheap method for ( 4 ). It may take time, but some day panda poo may help cars run. (296 words)

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英語 高校生

問題解いたのですが答えをしりらないので合ってるか分かりません。どなたか教えてください🙏

テーマ 資源・エネルギー 10 文法項目 動名詞(いろいろな形/動名詞と不定詞) Track 29-30 UNIT 6 Reading URELL パンダのふんの研究が、いつの日か環境問題の解決に寄与するかもしれません。 In June, 2016, a baby *giant panda, Tian Bao, was born at a zoo in Belgium. It became big news because the birth of a baby panda is an *extremely Actually, that of Tian Bao was only the sixth in Europe in the last 20 years. While its population is slowly increasing, the giant panda remains one of the rarest animals 5 in the world. Therefore, scientists have been doing research on how pandas have babies. So, you may think the scientists working at the Belgium zoo *accomplished the goal of their research. But they have another goal; apart from having done that research, they've been studying panda *poo. Why are they doing that? Bm Dimoda ro Tian Bao's mother Hao Hao and its father Xing Hui live in the same zoo as their baby does. While they enjoy sitting in the sun and eating bamboo, with ow dirg.or the scientist team collects their poo. By studying the poo, the team is aiming to understand how pandas can digest bamboo. rare event. 2 Note In fact, bamboo is receiving a lot of attention in biofuel research these days. 15 It's among the fastest-growing plants on earth, and yet needs the least care. So the plant can become a good source of *renewable energy. But because bamboo is very tough and hard to *degrade, today's method for making a biofuel from bamboo costs a lot. *Technically, pandas are meat-eating animals, but over the years the food they eat 20 has changed to almost only bamboo. The scientists are trying to find the *microbes that help a panda digest about 10kg of bamboo a day. By using these microbes, they will be able to discover an easy and cheap method for ( 4 ). It may take time, but some day panda poo may help cars run. (296 words)

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英語 高校生

オレンジの線が引かれてるところの文構造がわかりません。文構造の解説をしてほしいです🙇🏻‍♀️🙇🏻‍♀️

5 Many linguists predict that at least half of the world's 6,000 or so languages will be 1-11 デッド dead or dying by the year 2050. Languages are becoming extinct at twice the rate of endangered mammals and four times the rate of endangered birds. If this trend 20 continues, the world of the future could be dominated by a dozen or fewer languages. Even higher rates of linguistic devastation are possible. Michael Krauss, director of 1-12 ディバステーション the Alaska Native Language Center, suggests that as many as 90 percent of languages could become moribund or extinct by 2100. According to Krauss, 20 percent to 40 percent of languages are already moribund, and only 5 percent to 10 percent are "safe" in the sense of being widely spoken or having official status. If people "become wise 10 and turn it around," Krauss says, the number of dead or dying languages could be more like 50 percent by 2100 and that's the best-case scenario. The definition of a healthy language is one that acquires new speakers, No matter 1-13 how many adults use the language, if it isn't passed to the next generation, its fate is already sealed. Although a language may continue to exist for a long time as a second 15 or ceremonial language, it is moribund as soon as children stop learning it. For example, out of twenty native Alaskan languages, only two are still being learned by children. Although language extinction is sad for the people involved,) why should the rest of us care? What effect will other people's language loss have on the future of people who speak English, for example? (A)Replacing à minor language with a more widespread one may even seem like a good thing, allowing people to communicate with each other more easily. But language diversity is as important as biological diversity. Andrew Woodfield, director of the Centre for Theories of Language and Learning 1-14 in Bristol, England, suggested in a 1995 seminar on language conservation that people do not yet know all the ways in which linguistic diversity is important. "The fact is, no s one knows exactly what riches are hidden inside the less-studied languages," he says. Woodfield compares one argument for conserving unstudied endangered plants (that they may be medically valuable with the argument for conserving endangered languages. "We have inductive evidence based on past studies of well-known languages that there will be riches, even though we do not know what they will be. (B) It seems paradoxical but it's true. By allowing languages to die out, the human race is destroying things it doesn't understand," he argues. Stephen Wurm, in his introduction to the Atlas of the World's Languages in Danger 1-

解決済み 回答数: 1