学年

質問の種類

数学 高校生

この問題って、f(0),f(2)>0 を使って解いてもいいんでしょうか? 答えはあってました。 f(x)=x^2-2ax+3a

54 T ある変 基本例題 92 0≦x≦2の範囲において、 常に x²-2ax+3a> 0 が成り立つように、 の値の範囲を定めよ。 CHART & THINKING x 2の係数は正。 「常に x-2ax+3>0 が成り立つ」 ことから, 図1のように単にD<0 とするのは間 違い! 0x2の範囲」 となっているから, D>0 で図2のような場合も起こりうる。 「ある変域でf(x) > 0 (変域内の最小値)>0」 図1 と考えてみよう。 文字を含む2次関数の最小値は どのように求めればよかっただろうか。 → p. 114 基本例題 64 参照。 解答 f(x)=x2-2ax+3a とする。 求める条件は、0≦x≦2の範囲における関数 y=f(x) の最 小値が正であることである。 f(x)=(x-a)^-a²+3a であるから, y=f(x) のグラフは 下に凸の放物線で, その軸は直線 x =α である。 [1] α<0 のとき f(x) は x=0 で最小となる。 よって f(0)=3a>0 Dne [2] 0≦a≦2のとき f(x) は x=α で最小となる。 よって f(a)=-a²+3a> 0 すなわち これを解くと, a (a-3) < 0 から 0<a<3 これと 0≦a≦2の共通範囲は [3] 2 <a のとき 0<a≦2 f(x)はx=2で最小となる。 f(2)=4-a>0 よって これと 2 <α の共通範囲は 2<a<4 求めるαの値の範囲は①と② を合わせて 0<a<4 これは α<0 を満たさない。 ****** ゆえに (0fp) 025+zd a²-3a<0 ISATION ①0万不 MEMO (2) 01 20 x 02 定数 ( 図2 [1] 軸が変域の左外 02% [2] 軸が変域の内部 0a2 [3] 軸が変域の右外 Li V 02 基 Z C

回答募集中 回答数: 0
英語 高校生

英語の問題教えてください。 「英文法から学ぶ英作と読解」というテキストからです。 写真の問題を教えて頂きたいです。 解説や覚えておいた方がいい所などありました、そちらもよろしくお願いします。 写真と問題を書いておきます。 問題文を書いておきます。 1 次の質問に英語... 続きを読む

.... Reading Comprehension II 次の文章を読み、 後の問いに答えなさい。 Rakugo is a form of traditional Japanese spoken entertainment. It first became popular among people of the merchant class "chonin," and also spread to the lower classes during the Edo period. 16 A single rakugo performer appears on stage and kneels on a cushion. The performer wears a traditional Japanese kimono and usually has nothing except two stage properties: a paper fan and a hand towel. The fan can be used to represent a variety of things, such as a pipe, chopsticks, a pen, a fishing pole or a cup. Sometimes it creates sound effects. The hand towel can be used for things like a letter, a book or an actual towel. The comic story, which the performer narrates, is usually in the form of a conversation between two or more characters. The storyteller plays the two or three roles fluently and switches from one character to another by changing his voice, accent, or expression and turning his head, so the audience can imagine the scene. In the Meiji period, a British rakugo performer brought a lot of excitement to the audience. He was the first foreign-born rakugo perfomer, named Henry James Black, who adopted the stage name "Kairakutei Black." Everyone had a good laugh at hearing his comic tales and his fluent Edo dialect. 注 kneel on a cushion 座布団に座る sound effects have a good laugh at 〜 〜 に大笑いする

回答募集中 回答数: 0
英語 高校生

お願いします

1 Today, Taylor Swift is one of the most popular singers in the world, and is also al cover model for fashion magazines. But she was not always so popular. 2 Taylor Swift began singing country music in Pennsylvania when she was eleven. Country music is an older form of music in the USA that is usually enjoyed by 5 adults. Maybe this is why other kids at her school thought she was strange for stopped calling her. singing country music. Over time, these friends 3 One day, she invited many of her friends to go to the shopping center, but all of them said they were busy. So, Taylor went with her mother. When they got there, they saw all the girls shopping together without Taylor. Soon after that, Taylor 10 began eating lunch at school alone. (1): 4 Taylor asked her parents to take her to *Nashville, a city in Tennessee where many country singers and musicians worked. Her parents decided to move there to help her make her dream come true. Taylor's parents were right to believe she could succeed. At age fourteen, she got a contract with RCA Records, a major music 15 company. 5 RCA wanted Taylor to sing other people's songs until she was an adult. Taylor “ did not like this. She wanted to write and sing her own songs about her life and the boys she dated. The record company did not think older country fans would want to hear (3)a teenage girl talk about her life. 6 Taylor left RCA and joined a smaller record company that released her records. Her music became very popular with teenagers as well as older country music fans. Soon, Taylor was considered a major pop star, and young people who did not normally listen to country loved her music too. 5 7 One day she returned to Pennsylvania to do a concert. Girls from her old school came to the concert and were excited to see her. They treated her like a star, and seemed to have forgotten that they had stopped talking to her in junior high school. 20 Taylor realized her life had changed. (4) * Nashville + VIEN

回答募集中 回答数: 0
数学 高校生

なんのために最後に漸近線を求めているのですか?

重要 例題 78 z を 0 でない複素数とし,x,yをz+ 1 2 =x+yi を満たす実数,αを0<a</ を満たす定数とする。z が偏角 αの複素数全体を動くとき、xy平面上の点 (x, y) の軌跡を求めよ。 *U*2301 [類 京都大] 重要 26 解答 指針偏角αの範囲が条件であるから、極形式z=r (cosatisina) (0) を利用。 ■iの形に表すことにより,x,yをそれぞれr, aで表す。 12+- 2 つなぎの文字を消去 して,x,yだけの関係式を導く。なお、>0や0<a< より, xの値の範囲に制限がつくことに注意。 ゆえに TOADE z=r(cosatisina) (x>0,0<a</1/2)とすると ゆえに 0<a</であるから よって r+ cos a' - 1 (cosa + sina) == ² ( cos x r= 2 COS r 2 -=1から 練習 ③78 1 z+ -=r(cosa+isina)+¹(cosa-isina) 2 * = = =(r+ + )cosa+i(r— — )sina cosa, y=(r-1) sina x=(x+1/27) 1 x 2 cos a x² Acos2a 双曲線 w=z+. =r+ r a² cos a よって x≧2cosa また, >0 から ゆえに したがって 求める軌跡は osax + cos a>0, sin a>0 y sina y 表す図形 (2) r sin a したがって 4sin² a ここで, >0であるから, (相加平均) (相乗平均) により x²y² COS α -(tana)x<y<(tana)x 4 cos' a 4sin'α ;-). - / - ( 1 x =2 2. 等号はr=1のとき成り立つ。 _____________> +___>0, sina sin a COS α sina sina)=1 COS α COS α 63401 -=1のx≧2cosα の部分 < 絶対値や偏角αの範囲 に注意。 1 2 =-{cos(-a)+isin(-a)} ◄2+1/2=x z+ =x+yi 検討 第4章で学ぶ極 限の知識を用いて, y が実数 値全体をとりうることを調べ ることもできる。 lim m(x-¹)=∞, に lim (-1)=-∞であり, sinα> 0から lim y=-∞, limy = ∞ r+0_ →0 点 (x, y) の軌跡は次の図の 部分。 (0) y=(tana)x を求めている -2cosa / 2cosa y=-(tana)x 0 でない複素数zが次の等式を満たしながら変化するとき, 点z+-が複素数平 面上で描く図形の概形をかけ。 (1) |2|=3-(2) |z−1|=|z-i| 139 2章 10 媒介変数表示

回答募集中 回答数: 0
英語 高校生

全文訳お願いします!

4 20 科学 420 words Chapter 1 The recipe for making any creature is written in its DNA. So last year, when 1-1 geneticists* published the near-complete DNA sequence of the long-extinct woolly mammoth, there was much speculation about whether we could bring this giant creature back to life. 5 東京理科大学 Creating a living, breathing creature from a genome* sequence that exists only in a computer's memory is not possible right now. But someone someday is sure to try it, predicts Stephan Schuster, a molecular biologist at Pennsylvania State University and a driving force behind the mammoth genome project. So besides the mammoth, what other extinct beasts might we bring back to life? Well, 12 10 it is only going to be possible with creatures for which we can recover a complete genome Without one, there is no chance. And usually when a creature dies, the (1) - DNA in any flesh left untouched is soon destroyed as it is attacked by sunshine and bacteria. sequence. There are, however, some circumstances in which DNA can be preserved. If your 15 specimen froze to death in an icy wasteland such as Siberia, or died in a dark cave or a really dry region, for instance, then the probability of finding some intact stretches of DNA is much higher. Even in ideal conditions, though, no genetic information is likely to survive more than a million years. - so dinosaurs are out and only much younger remains are likely to yield good-quality DNA. "It's really only worth studying specimens that are less than 100,000 years old," says Schuster. The genomes of several extinct species besides the mammoth are already being sequenced, but turning these into living creatures will not be easy. "It's hard to say that something will never ever be possible," says Svante Pääbo of the Max Planck Institute 25 for Evolutionary Anthropology in Germany, "but it would require technologies so far removed from what we currently have that I cannot imagine how it would be done." But then (3) 50 years ago, who would have believed we would now be able to read the instructions for making humans, fix inherited diseases, clone mammals and be close to creating artificial life? Assuming that we will develop the necessary technology, we have 30 selected ten extinct creatures that might one day be resurrected. Our choice is based not just on practicality, but also on each animal's "charisma" - just how exciting the prospect of resurrecting these animals is. 1-3

回答募集中 回答数: 0