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Mathematics Senior High

なぜこの範囲なのですか?

OP=2, ZPOH=0であるから,Pの座標は よって, Sは 20+α=90° のとき最大値 12(V5+1)をとる。 計> AQKHの面積を求めるには、辺KH, QK の長さがわかればよい。そのためには,点P 半径rの円x+y=r?上の点 A(x, y) は,x=rcosa、 y=rsina (aは動径OAの表 す角)とおけることと, ZPOQ=90° より,ZQOH= POH+90° であることに着目。 象限を動く点である。ただし,原点Oに対して, 常に ZPOQ18 であるとす 更にZPOH=0とする。このとき、AQKH の面積Sは tan0="コのと きをもつ。まず,これを書き DOO00 +cの最大値を求めよ。 253 を動く点で x また。 る。 基本 152) をとる。 す。 最大値C き。 用できる。 【類早稲田大) 重要159) 点Qの座標を式に表すことがポイント。 4章 (2cos 0, 2sinθ) 27 が消去できた形になる。 って,以後はBのみを 三ればよい。 Q 4 (4cos(0+90°), 4sin(0+90°)) すなわち(-4sin0, 4cos0) S=KH-QK=;(2cosθ+4sin0)-4cosé ただし 0°<0<90° 1 -4 K 0 6H2× ゆえに =2(2cos?0+4sin@cos0) =2(1+cos 20+2sin20)=2{V5 sin(20+α)+1} 辺 三理 sin角 外接円の半径) 三角関数の合成。 2 0°<a<90°を満たす角。aは具体的な角として表す , COS α= 75 (0°<) α<20+α<180°+α (<270°) ただし,aは sina=ー ことはできない。 の公式を利用する。 『くの<90°から 1 20+a=90°のとき tan 20=tan(90°-α)= tan α COS α 1 =2 sina Asina= V5 2 Cos α= のとき, 2tan 0 -=2 よって tan?0+tan0-1=0 となるから, (tan0 についての2次方程 式とみて解く。 ゆえに 1-tan'0 アー1+ 5 tan 0= となるのは、 自形のときで 『くB<90° より tan 0>0 であるから 2 後習|0を原点とする座標平面上に点 A(-3, 0) をとり, 0°<0<120° の範囲にある0 162 に対して,次の条件(a), (b) を満たす2点B, Cを考える。 (a) Bはy>0の部分にあり, OB=2かつ ZAOB=180°-0である。 (b) Cはy<0の部分にあり, OC=1かつ ZBOC=120° である。ただし, AABC は0を含むものとする。 (1) A0ABと AOACの面積が等しいとき, θの値を求めよ。 (2) 0を0°<0<120° の範囲で動かすとき, △0ABと △0ACの面積の和の最大 値と,そのときのsin0の値を求めよ。 する。 三社大) (東京大) 104

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Mathematics Senior High

なぜ点Qの座標がrcos(‪α‬+π/3)なのですか?

「点P(3, 1)を,点 A(1, 4) を中心として だけ回転させた点をQとする。 232 OO0 基本 例題148 点の回転 25 π 点P(3, 1)を,点 A(1, 4) を中心として今だけ回転させた点を9と。 (1) 点Aが原点Oに移るような平行移動により,点Pが点Pに移るし 基 π 点P'を原点0を中心として (2)点Qの座標を求めよ。 2 3 p.227 基本事項 ソト 指針> 点P(xo, Yo) を, 原点 Oを中心として0だけ回転させた点を Q(x, y)とする。 OP=rとし,動径 OP とx 軸の正の向きとのなす角を αとす Q(rcos(a+0、 Tsinla+ ると Xo=rcos α, o=rsina SP 0 (Tcosa、 Y OQ=rで,動径 OQ とx軸の正の向きとのなす角を考えると, 加法定理により x=rcos(α+0)=rcosαcos0-rsinαsin0=xocos0-yosin0 ソ=rsin(α+0)=rsinacos0+rcosαsin0= yo Cos 0+ xosin0 この問題では,回転の中心が原点ではないから, 上のことを直接使うわけにはいかない。 で,3点P, A, Qを,回転の中心である点Aが原点に移るように平行移動 して考える。 二情 CD _rsu 0 0 YSna エ十xを 解答 (1) 点Aが原点0に移るような平行移動により,点Pは点 P'(2, -3)に移る。次に, 点Q' の座標を(x', y)とする。 また,OP'=r とし,動径 OP' とx軸の正の向きとのなす角 |x軸方向に-1, y軸方向 に-4だけ平行移動する。 129 nst 13 S65 をαとすると 2=rcos a, -3=rsina S65 よって デーrco(a+号)rcomcosーrsinasin よって x'=rcos{α+ =rcos a COS 3 -rsinasin- 3 3+ イrを計算する必要はない。 1 =2. 3 2+3/3 2 ゾ=rsin(a+ 2 2 4 4 π =rsinacos+rcos asin 3 → TA Sin3 ち向の五O 1 13_2/3-3 三ー 2 2 2 2+3/3 2/3-3) 2 Boe nspns 0NV2 |3 したがって、点Q’の座標は 万3

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Mathematics Senior High

この問題の①が全然分かりません! 細かく教えてください🙇🏼‍♀️

OOOO0 「辺の長さがaである正四面体 ABCD がある。 (1) この正四面体の高さをaの式で表せ。 (2) この正四面体の体積をaの式で表せ。 基本例題1.35 正四面体の高さと体積 基本134 CHARTOSOLUTION 空間図形の問題 平面図形(三角形)を取り出す (1) まず,高さを辺にもつ三角形に着目→頂点Aから底面△BCD に垂線 Arr の半径)はABCD における正弦定理から。 (2)(四面体の体積)=× (底面積)×(高さ) 解答 (1) AABH, △ACH, AADH は,斜辺の長さ がaの直角三角形で AH A (1) 正四面体の頂点Aから底面ABCD に垂線 AH を下ろすと 0 0 は共通辺である。 直角三角形において, 斜 辺と他の1辺が等しいな らば互いに合同である。 AABH=△ACH=△ADH よって BH=CH=DH D B ゆえに,点HはABCD の外接円の中 心で,外接円の半径は BH である。 よって,ABCD において, 正弦定理 H C により でるさケ 0< O CD a a BH= =2R 2 sin60° V3 sin ZDBC したがって CD=a, ZDBC=60° ATー A *AABH に三平方の定理 2 a AH=VAB?-BH° = a v3 を適用。 4。 /2 V6 a 先公のくロへ 3 a 3 (2) ABCD の面積は 3 B H a *aasin60°= -a? V3 三 4 ABCD の面積 よって,正四面体 ABCD の体積は Tew -BD·BCsin ZDBC .ABCD·AH== 3 1 .V3 e.16 2 3 4 3 aミ -a 3 12 三 く白

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English Junior High

答えがない高校の過去問です。 回答確認のために教えてほしいです。

【2】次の英文を読んで, 下の(1)~ (5)の英文の( を書きなさい。 )に当てはまる最も適当なものを, それぞれア~エの中から1つずつ選び, その記号 *Ogasawara Islands are a group of islands in *the Pacific Ocean, about. 1000 kilometers south of Tbkyo. There are more than 30 islands, and about 3000 people live on the two largest islands. They are sometimes called “Tolyo's *Hidden Islands' or **the Galapagos of the East". When Ogasawara people go to Tbkyo, they have to take a ferryboat for 24 hours because there is no airport. Ogasawara Islands are far from the main islands, so there are many kinds of *unique plants and animals.They are called *endemic species. Thirty - six percent of the plants on the islands'are endemic species. We can see those plants only in Ogasawara Islands. Because only plants and animals that have *adapted to Ogasawara *environment could *survive, unique *ecosystems were developed. This is a story about people who saved two kinds of animals on Ogasawara Islands. One is a red-headed wood pigeon, Karasu Bato".: This is one of the endemic species on Ogasawara Islands. Birds usually live on trees and *protect themselves from their *enemies. But red-headed wood pigeons on the islands have no enemies, so they live on the ground. Their living environment has changed since people brought cats to the islands as pets. Some of them *went wild and became *stray cats. Amother cat usually has about 20 babies a year, so the number of the stray cats *kept increasing and a lot of pigeons were eaten by them. In 2002, the number of the pigeons was only about 40. People began to think they should do something to protect this endemic species and natural environment on Ogasawara Islands. In 2008, people on the islands, Japanese and *overseas researchers, *public officials and animal doctors met together and started a project to save the pigeons. At thé meeting, they decided to *get rid of the stray cats, but they didn't know what to do. So after the meeting, they asked *the Tbkyo Veterinary Medical Association for advice. Animal doctors in this association *cooperated with a lot of volunteers and started a project to save the stray cats. They said, “The pigeons can't survive outside the islands, but cats can live in Tokyo. We want to save both kinds of animals,” The stray cats were *caught and carried to Tbkyo by ship. Animal doctors and volunteers took care of them and looked for their new fanmilies. From 2008 to 2018, about 800 stray cats were sent to Tokyo to start their new ife. Also, the number of pigeons has increased to about 400 now. This story shows that people may have a bad *influence on the natural environment, but we can protect and make it better by cooperating with each other. A person who took part in this project said, “It is important for us to think how we can keep the natural environment for the future." “Aka-gashira *the Pacific Ocean 太平洋 *unique 独特の *environment 環境 *went wild 野生化した *Hidden 隠された *endemic species 固有種 *ecosystems 生態係 (注) *Ogasawara Islands 小笠原諸島 *the Galapagos ofthe East 東洋のガラパゴス *adapted adapt 「適応する」 の過去形·過去分詞 *protect~ ~を守る *kept increasing 増え続けた *get rid of ~ *suIvive 生き残る *stray cats ノラネコ *public officials 公務員 *enemies 敵 *overseas researchers 海外の研究者 *c0operated 協力した ~を駆除する *caught catch 「~をつかまえる」の過去形·過去分詞 *the Tokyo Veterinary Medical Association 東京都獣医師会 *influence 影響

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English Junior High

答えがない高校の過去問です。 回答確認のために教えてほしいです。

【2】次の英文を読んで, 下の(1)~ (5)の英文の( を書きなさい。 )に当てはまる最も適当なものを, それぞれア~エの中から1つずつ選び, その記号 *Ogasawara Islands are a group of islands in *the Pacific Ocean, about. 1000 kilometers south of Tbkyo. There are more than 30 islands, and about 3000 people live on the two largest islands. They are sometimes called “Tolyo's *Hidden Islands' or **the Galapagos of the East". When Ogasawara people go to Tbkyo, they have to take a ferryboat for 24 hours because there is no airport. Ogasawara Islands are far from the main islands, so there are many kinds of *unique plants and animals.They are called *endemic species. Thirty - six percent of the plants on the islands'are endemic species. We can see those plants only in Ogasawara Islands. Because only plants and animals that have *adapted to Ogasawara *environment could *survive, unique *ecosystems were developed. This is a story about people who saved two kinds of animals on Ogasawara Islands. One is a red-headed wood pigeon, Karasu Bato".: This is one of the endemic species on Ogasawara Islands. Birds usually live on trees and *protect themselves from their *enemies. But red-headed wood pigeons on the islands have no enemies, so they live on the ground. Their living environment has changed since people brought cats to the islands as pets. Some of them *went wild and became *stray cats. Amother cat usually has about 20 babies a year, so the number of the stray cats *kept increasing and a lot of pigeons were eaten by them. In 2002, the number of the pigeons was only about 40. People began to think they should do something to protect this endemic species and natural environment on Ogasawara Islands. In 2008, people on the islands, Japanese and *overseas researchers, *public officials and animal doctors met together and started a project to save the pigeons. At thé meeting, they decided to *get rid of the stray cats, but they didn't know what to do. So after the meeting, they asked *the Tbkyo Veterinary Medical Association for advice. Animal doctors in this association *cooperated with a lot of volunteers and started a project to save the stray cats. They said, “The pigeons can't survive outside the islands, but cats can live in Tokyo. We want to save both kinds of animals,” The stray cats were *caught and carried to Tbkyo by ship. Animal doctors and volunteers took care of them and looked for their new fanmilies. From 2008 to 2018, about 800 stray cats were sent to Tokyo to start their new ife. Also, the number of pigeons has increased to about 400 now. This story shows that people may have a bad *influence on the natural environment, but we can protect and make it better by cooperating with each other. A person who took part in this project said, “It is important for us to think how we can keep the natural environment for the future." “Aka-gashira *the Pacific Ocean 太平洋 *unique 独特の *environment 環境 *went wild 野生化した *Hidden 隠された *endemic species 固有種 *ecosystems 生態係 (注) *Ogasawara Islands 小笠原諸島 *the Galapagos ofthe East 東洋のガラパゴス *adapted adapt 「適応する」 の過去形·過去分詞 *protect~ ~を守る *kept increasing 増え続けた *get rid of ~ *suIvive 生き残る *stray cats ノラネコ *public officials 公務員 *enemies 敵 *overseas researchers 海外の研究者 *c0operated 協力した ~を駆除する *caught catch 「~をつかまえる」の過去形·過去分詞 *the Tokyo Veterinary Medical Association 東京都獣医師会 *influence 影響

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English Senior High

この教科書のレベルはどのくらいですか教えください この教科書でどのくらいのレベルの大学まで対応できますか?

1 On 10 February 2009, at a height of about 800 kilometers above Siberia, an American satellite collided the first such height [háit] satellite [séetalait] collide(d) [kaláid(id)] with an old Russian satellite. It was collision [kaligan] collision in the history of space development. As a result, fragment(s) [fráegmant(s)) debris [dabri:] more than 1,000 fragments of debris were scattered into space. 2 The image above shows the vast amount of space debris in orbit around Earth. Approximately 22,000 vast [váest] orbit [5:rbat] approximately [aprá:ksamatli) objects larger than 10 centimeters across are floating around Earth. Of these, about 16,000 are from known 10 considering [kansidarig) artificial [a:rtafijal] currently [ks:rantli] operation [a:paréifon] Considering that there are only about 1,000 artificial satellites currently in operation, the amount of Sources. space debris is astonishing. This space debris is not only due to the collision of satellites. For example, when rockets reach space, they s 15 leave behind surplus engines and fuel tanks. These objects remain in orbit as space debris. In addition, surplus s5:rplas] there are tools that astronauts have dropped while tool(s) [t:l(z)) astronaut(s) [astrand:t(s) aluminum [ala:manom per|par] working outside. Even a one-centimeter aluminum ball. when orbiting at a speed of around 10 kilometers per 0 bullet [bálat] second, is far more powerful than a bullet from a gun. gun [gán]

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