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数学 高校生

どうして線を引いたところがイコールだとわかるのですか?

4 00000 重要 例題 164 三角形の面積の最小値 面積が1である△ABCの辺AB, BC, CA 上にそれぞれ点D, E, Fを AD: DB=BE: EC=CF: FA=t: (1-t) (ただし, 0<t<1) となるようにと る。 (1) △ADF の面積をtを用いて表せ。 基本 158 (2) △DEF の面積をSとするとき, Sの最小値とそのときのtの値を求めよ。 指針 (1) 辺の長さや角の大きさが与えられていないが, △ABCの面積が1であることと ANDA △ABCと△ADF は∠Aを共有していることに注目。 AABC= C=1212AB・ACsin A (=1), ADF=1/12AD (2) △DEF=△ABC-(△ADF+△BED+△CFE) として求める。・・・・・・ Sはtの2次式となるから、基本形 a (tp)'gに直す ただしtの変域に要注意! $46-(03/ 解答 (1) AD=tAB, AF=(1-t)AC であるから AADF=AD AF 2 -AD よって AABC= AF sin A =1/12t(1-t) AB・ACsin A c=1/12/1 -AB・ACsinA=1 2) (1) と同様にして よって △ADF= =AD-AF sin A Dante (bo+de) コーナ AADF=t(1-t). AB AC sin A =t(1−t) BtE ゆえに, 0<t<1の範囲において, Sは t=1のとき最小値 ADA 1-t S=△ABC-(△ADF + BED+△CFE) =1-3t(1-t)=3t2-3t+1=3t- SUBAS -t t = 3(t-1- ) ² + 1 (*) 4 2009-0 (8-2081) 805 00 AS をとる。 $301 検討 一般に AB'AC' AAB'C' = △ABC AB AC A B (*) 3t²−3t+1=3(t²−t)+1 ABED=ACFE=t(1-t) (n==312-t+(1/2)}-3(1/2)+ SA S-31²-3t+1 4 B' 基 17 最小 C M 指

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数学 高校生

⑶の質問です y=2^x+1のままlog₂を付けると、log₂1=0より x=log₂y となってしまうと思うのですが、何故解答と変わってくるのでしょうか?

56 基本例題 95 逆関数の求め方とそのグラフ 次の関数の逆関数を求めよ。 また, そのグラフをかけ。 3 (1)y=- -+2 (x>0) (2) y=√-2x+4 x 指針▷ 逆関数の求め方 関数y=f(x) の逆関数を求める。 y=f(x) について解く x=g(y) また 解答 3 (1) y= +2(x>0) x ①の値域はy>2 ①をxについて解くと, y>2であるから 求める逆関数は,xとyを入れ替えて グラフは,図 (1) の実線部分。 (2) y=√-2x+4 ①の値域は y≥0 ! ①をxについて解くと, y2=-2x+4から 求める逆関数は, xとyを入れ替えて y=- x²+2(x²0) グラフは,図 (2) の実線部分。 (3) y=2x+1 ① の値域は y>1 ①をxについて解くと, 2=y-1から 求める逆関数は,xとyを入れ替えて グラフは,図 (3) の実線部分。 (1) YA! (2) 2 この形を導く。 (f' の定義域)=(fの値域)(f' の値域)=(f の定義域) Wi-x 20 ...... 2 x ① 2 SO y= 3 X=- 関 y-2 3 x-2 x=- (3)_y=2*+1 p.165 基本事項 ①,2② 2 xとyを交換 y=g(x) ↑ これが求めるもの。 に注意。 こう(笑) HOCS HA 00000 Xx トの値域を調べる。 [ xy=3+2x から 重要 97 まず、与えられた関数 ① 意くことに数①の値域である。 1 2 y² +2 (y-2)x=3 (top) y2であるから,両辺を y-2で割ってよい。また、 逆関数の定義域はもとの関 J (④)はありx≧0 を忘れないように! x=log2(y-110g.2学院大 y=log2(x-1) YA 3 2. W f(x) f-¹(x) 定義域 値域 値域 = 定義域 - 定義域は x> 1 CASTROHO (x) (x) (3) (90 1 34C 0 1 2 3 10 x 10 ULCERO SARTJEDx=y #1 (0.003

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英語 高校生

1問でも構いません教えてください🙇‍♀️

Every sentence has a mistake. Correct the mistake in each sentence. don't Fernando and Carlos doesn't have a car. Example: 1) Do you live in campus, with family, or with friends? 2) Susan doesn't like go to the library in the morning. 3) What time does class finishes in the afternoon? 4) I like to sing, but I can't a musical instrument. 5) I like to play ski in winter. 6) There aren't some coffee shops near here, I'm afraid. 7) Excuse me. Where's post office, please? 8) I like it here, but there are a lot of noise. 9) Turn left onto Main Street and it's to the left. 10) Hey! Is that your sunglasses over there? 11) How much this coffee, please? 12) I live behind of a large supermarket. Part V- Grammar (16 points) Write ONE word in the space to complete the sentences. 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) Go 14) Are 15) How 16) you work in Singapore? do they study there? My cousin My friend Helen "Do they study at university?" "No, they I like. My girlfriend study. He works. her homework in the library. play my guitar in the evening. There aren't How do I Is there a grocery store. aerobics, but she doesn't like yoga. he ski?" "No, he can't." there a good restaurant near the hotel? coffee shops in this street. to the City Hospital? here? ahead. It's next to the Italian coffee shop. shoes over there yours? is this pen? store is expensive. Let's go to another store.

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英語 高校生

文章を読み200字以内の日本語で要約して欲しいです

Ⅰ 以下の英語の文章を200字以内の日本語で要約しなさい。 ad a We often forget that an important part of "scientific" knowledge was built on the study of alchemy and other magical practices Alchemists were interested in changing certain metals into more valuable ones For example they tried to change lead into gold, However, they also wanted to produce medicines (that would allow people to live forever or cure any disease. The philosopher's stone is known to us today from the Harry Potter series of To novels and movies This magical stone was believed to have enormous powers and make you capable of doing and knowing pretty much everything. 可能にする *John Dee was an alchemist (who was particularly interested in the problem <of foretelling the future from the positions of the stars and other planets He was also an expert in ordinary mathematics and navigation, One of his most * ふつう fell important projects involyed, research (on a universal language (for 巻き込む communicating with angels!Dee was extremely successful He made a lot of money/had (extremely high status (in universities and government, and owned one of the best libraries in Europe/much of it dedicated to magic. 捧げる However towards the end of the sixteenth century/ideas about magic were changing. Many Christians in England were unhappy(that people were still キリスト教入 communicating with the spirit world which was one of the goals of sixteenth century magicians, As you know Japanese people welcome the spirits of ancestors into the house during the Bon festival European Christians were not happy (about that kind of thing, and they complained (about similar European festivals like Halloween) At the same time, many Christians were afraid that alchemists might be trying to steal God's power. As a result, there was a powerful movement to shut down magic once and for all. 禁止する ALE V n You may be familiar with the Japanese manga and anime series *Fullmetal 45% a Alchemist./The story takes place (in a fictional world in which alchemy continues to function as a normal part of scientific knowledge For example> the heroes (of the series are searching for the philosopher's stone,/and alchemists carry out important work(on behalf of the government/If our 利益 modern world had developed (in the same way as the world of Fullmetal Alchemist people like John Dee would probably have continued to do well. In fact, he lost his jobs and money and died in poverty. 1

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