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数学 高校生

数学I、二次関数の問題です。 問3で、解説にある(丸をつけてます)x=-2と、x=0の時を検討しなければいけない理由がわかりません。 教えてください

ここで, 0°<8<180°において, tan 0<0だか 5 cos <0 よって cos0- 1 √10 V10 10 AB=c とおくと, 余弦定理により 7=c+3-2c3cos60° e-3c-40=0 (+5)(c-8)=0 >0より,c=8 AB=8 よって また, 正弦定理により 8 7 sin C sin 60° したがって sinC= 8v3 4√√3 7 2 7 A 60° 放物線 ①がx軸と異なる2点で交わるので (2) a²-4.1.6>0 を共有する。 (1)より-4(3a-5) > 0 a-12a+20>0 (a-2) (a-10)>0 よってa<2, 10<a このとき、放物線 ①とx軸との交点のx座標は, x+ax +3a-5=0を解いて -a±√a² よって、条件に適する。 したがって, (i), (ii), ()より求めるαの 値の範囲は 1<a≦ 5 3 a=2 4 -12a+20 x=- 2 よって AB=√2-12a+20 AB=2のとき, AB2=4より a²-12a+20=4 a²-12a+16=0 a=6±2√5 (1) 余弦定理により cos A=- CA' + AB-BC2 2.CA.AB 52+82-72 1 2 2.5.8 よって ∠A=60° また 数学 3 こtax- 放物線y=x+ax+b ① (a, bは定数)は、 基本 (1) bをを用いて表せ。 b=30-5 (2) 放物線①がx軸と異なる2点A, Bで交わるよう また,AB=2となるようなαの値を求めよ。 (3) -2<x<0において, 放物線 ①がx軸と1点の 4= 9-7972 B 1 C ABC= -4-2sin 135.4.2.2 2 AD=xとすると BD = 1/12.4.2 =2√2 ・4.xsin 45° B D 135° C 1 ・4・x・ =√2x 2 =90° より ADC=12.2.x=x 2 △ABD + △ADC = ABC だから +x=2v2 2√2 ゴー =2√2 (√2-1)=4-22 √2+1 _7 + 9 + 9 + 10 +9+ 4 ) = 8 分散 s' は 1/11 (78)2+(9-8)+(9−8) 2 + (10−8)2 + (9-8)+(4-8)^1 4 標準偏差sは 4 これは,a2, 10 <αに適する。 したがって a= 6±2√5 (3) f(x)=x2+ax+3a-5... ①' とおく。 (i) x=-2,0がf(x)=0の解でないとき -2<x<0において, 放物線 ①がx軸と1 点のみを共有するのは,次の2通りである。 (ア) 放物線 ①が-2<x<0の範囲でx軸と1 点で交わるとき f(-2)f(0) <0より (a-1)(3a-5)<0 5 よって1<a</ a-1 13a-5 (イ) 放物線 ①が-2<x<0の範囲でx軸と 接するとき a²-4 (3a-5)=0.2 a -2 <- <0...... ③ 2 ② より a=2,10 ③より 0<a < 4 よって a=2 (i) x=-2がf(x)=0の解のとき 0 -5 ① より 4-2a+3a-5=0 よって a=1 このとき f(x)=(x+2)(x-1)となるからグ ヘラフは2<x<0の範囲でx軸と交わらない。 (i) x=0がf(x)=0の解のとき △ABC123CAAB sin 60 2 5.8.3 =10√√3 したがって, ABCの面積は 10√3 (2) 内接円の半径を とすると, △ABC=△IAB+ △IBC + △ICA だから 10√3=1/28r+1/27r+1/1/25 =10r •7•r+ よって,r=√3 したがって IH=3 また, AIはAの二等分線だから ZIAH=30° よって ∠AIH=60° ゆえに AH=v3tan 60° したがって AH=3 C 30° 13 A 30°H B (3) (外接円の半径) = OAだから, 正弦定理により 7 7 OA= 2 sin 60° √3 応用 , 点 (-3, 4) を通るので 2+α (-3)+6 Ba-5 5 ①'より 3a-5=0 よって a= 3 このとき(x)=x(x+g)となるからグラフは 2<x<0の範囲でx軸と1点 (一号 0) よって 3 Oは辺ABの垂直二等分線上にあり、Mは辺 ABの中点であるから AM4 よってOM=VOAAM2 a²-4a²-4(30-5) ca² (zat= Ja²-120+20 9212a419:0 +8 a=6±√ 17 るこ 1: (249) 2 a²-12 -2(-1 ac2,10 (53) +10=30 13 4 →

解決済み 回答数: 1
英語 高校生

赤線部分についてです。私は「any species」を「いかなる種」と訳したのですが、日本語訳や解説を見るに、"any species"は"a species"という意味を表してるそうです。今までanyにひとつの物を限定するイメージを持っておらず、調べてもあまり理解できなか... 続きを読む

2 Unit 20-Cognitive Linguistics- | 519 words / 筑波大 1 識別 One of the most important things that language does for us is help us make distinctions. implicitly, automatically all other When we call something edible, we distinguish it from - R オ 2 5 things that are inedible. When we call something a fruit, we necessarily distinguish it from vegetables, meat, dairy, and so on. 初期の人 組織した。彼らの精神と 基本的な私たちがまた 有効的に ② (1) Early humans organized their minds and thoughts around basic distinctions/that we still make and find useful. One of the earliest distinctions made was between now/and not-now; / these things are happening in the moment these other things happened in the past and are now in my memory. No other species makes this self-conscious distinction among past, present, and future. Of course many species respond to time by building nests, flying south, hibernating", 10 mating but these are preprogrammed, instinctive behaviors and these actions are not the 物体の永抂 result of conscious decision, meditation, or planning. 13 Simultaneous with an understanding of now versus before is one of (2) object permanence: Something may not be in my immediate view, but that does not mean it has ceased to exist. Our 存在をつかむではない? 何かはすぐには見えないかも brains represent objects that are here-and-now as the information comes in from our sensory 2 15 receptors For example, we see a deer and we know through our eyes that the deer is standing n& right before us! When the deer is gone we can remember its image and represent it in our mind's eve, or even represent it externally by drawing or painting or sculpting it. Jon 上の 4 This human capacity to distinguish the here-and-now from the here-and-not-now.showed up 初の記校 なだがここにあって、何がここにあったか at least 50,000 years ago in cave paintings. (3) These constitute the first evidence of any species on 芝援 識別 ひきる 120 earth being able to explicitly represent the distinction between what is here and what was here. In as other words those early cave-dwelling Picassos, through the very act of painting, were making a distinction about time and place and objects, an advanced cognitive operation we now call mental representation* And what they were demonstrating was an articulated sense of time: There was a deer out there (not here on the cave wall of course). He is not there now, but he was there before. 25 Now and before are different; here (the cave wall) is merely representing there (the meadow in front of the cave). This prehistoric step in the organization of our minds mattered a great deal. 5 In making such distinctions, (4) we are implicitly forming categories, something that is often す overlooked The formation of categories in humans is guided by a cognitive principle of wanting 多くの何報をできる! 325 h to encode as much information as possible with the least possible effort. Categorization systems optimize* the ease of conception and the importance of being able to communicate about those hibernate 冬眠する sensory receptor: 感覚受容器 (体の周囲の環境情報を感知する受容器の総称。 目、鼻、耳など) cognitive : 認識の mental representation 的表象(例えば人が「イヌ」を考えるとき、それは頭の中で文字でも映像でも 音でもない 何らかの形で思い描かれるが,この「頭の中の記号」のことを心的表象という) encode:・・・を記号化する optimize ... を最大限にする permeate : ・・・ に広がる 英 6 音

解決済み 回答数: 2
英語 高校生

問4の⑤の計算はどうすれば合うのですか。 教えてください🙇‍♀️ 3枚目が答えです。

次の英文を読んで,下の設問に答えなさい。 Last year, 4.2 million babies died. That is the most recent number reported by UNICEF of deaths before the age of one, worldwide. We often see lonely and emotionally charged numbers like this in the news or in the materials of activist groups or organizations. They produce a reaction. Who can even imagine 4.2 million dead babies? It is so terrible, and even worse when we know that almost all died from easily preventable diseases. And how can anyone argue that 4.2 million is anything other than a huge number? You might think that nobody would even try to argue (that, but you would be wrong. That is exactly why I mentioned this number. Because it is not huge: it is beautifully small. If we even start to think about how tragic each of these deaths is for the parents who had waited for their newborn to smile, and walk, and play, and instead had to bury their baby, then this number could keep us crying for a long time. But who would be helped by these tears? Instead let's think clearly about human suffering. The number 4.2 million is for 2016. The year before, the number was 4.4 million. The year before that, it was 4.5 million. Back in 1950, it was 14.4 million. That's almost 10 million more dead babies per year, compared with today. Suddenly this terrible number starts to look smaller. In fact (2)the number has never been lower. Of course, I am the first person to wish the number was even lower and falling even faster. But to know how to act, and how to prioritize resources, nothing can be more important than doing the cool-headed math and realizing what works and what doesn't. And this is clear: more and more deaths are being prevented. comparing the numbers. (3). We would never realize that without

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