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数学 高校生

丸をつけているcos角MLNはどうしてこうなるのですか。 LMNだとだめですか?

空間図形の問題 平面図形 (三角形)を取り出す | 線分 AM, AE, EM の長さをそれぞれ求めよ。 |2) ZEAM=0 とおくとき, cos@の値を求めよ。 ALMN の面積は, 3辺の長さがわかれば, 求められる(p.198 基本例題 128 (1) 参 「辺の長さが6の正四面体 OABCがある。辺OAの中点をL, 辺OB を 照)。辺LM, MN, NL をそれぞれ△OLM の辺, △OMN の辺, △ONL の辺と 134 立体の切り口 面四2 000O0 本例題 205 内接 事項2 ーズ 顔を求めよ。 基本 128 OLUTION 基本 135 スペー CEART O 歯強が 与 して,余弦定理により求める。 雪 ALOM=ZMON LM=OL'+OM*ー2·OL·OMcos60° 1 1ONフ= =3'+4°-2-3-4=13 O-60° MN°=OM°+ON。-2·OM·ONcos 60° 4 NN L 4 4章 =+2°-2-4-2=12 Hd っよい。 NL=ON°+OL?ー2·ON·OLcos60° M 2 15 =2°+3°-2-2-3=7 ゆえに, LM>0, MN>0, NL>0 であるから LM=/13, MN=2V3, NL=/7 よって,ALMN において, 余弦定理により LM°+NL?-MN? 2.LM·NL 外換する味 まま と、 13+7-12 2/13/7 V91 75 5/3 V 91 V91 6= 4 COSZ MLN= レールル 2 4 sinZMLN=/1- |inf. 3辺の長さが与えら れた場合,ヘロンの公式か ら三角形の面積が求められ るが,この場合は 2s=/13 +23+/7 となり,計算が煩雑になる。 ゆえに ALMN=→LM·NL sinZMLN 2 したがって 6 13/7… 5/3_5/3 2 V91 he であ PRACTICE… 134° BCD-VH-T 辺CDの中点をMとする。 日A き (大阪教育大) AAEMの面積を求めよ。 目。 $は 三角形の面積,空間図形への応用

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英語 中学生

教えてください🙏🙇‍♀️🥺

Hideki: Great! His dream finally came true! Hideki: Did Ranald have a hard time in Nagasaki? ME Smith: Well, this book says that people were kind to him because they thought he was a nice person. Me Smith: However, he was caught soon and taken to Nagasaki as an *illegal immigrant. Me Smith: Ranald didn't give up his dream. He worked on a ship, and he tried to find a way to go to Me Smith: Well, he had to take a *ship to Japan because planes were not *invented yet. Also Japan was Hideki: An isolated country Oh, Sakoku! I understand why it wasn't easy for him. was very interested in Japan. He wanted to visit Japan, but it wasn't easy. 読んで、 Hideki: Why? on isolated country at that time. Tonan, One day he got off a ship *off the coast of Hokkaido. Then he took a small *boat and 0oched an island in Hokkaido. He did this when he was 24 years old. In Nagasaki, he taught English, and he also learned Japanese from Japanese people. After seven months in Nagasaki, he went back to America and wrote about Japan and Japanese people. From his book we can understand his love for Japan. Oh, even on his *grave stone we can see it. Hideki: What do you mean? ME Smith: It has the Japanese word Sayonara on it. Hideki: I understand he liked Japan very much. He became a *bridge between two countries. To be like him in the future, 5 Mr Smith: That's good. Do your best, Hideki. invent:発明する isolated:孤立した 注) native English-speaker: 英語を母国語として話す人 off the coast of ~:~の沖合で ship:船 boat:ボート illegal immigrant: 密入国者 grave stone:墓石 bridge:かけ橋

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