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数学 高校生

次の問題で青いところがよく分からないのですがどなたか解説お願いします🙇‍♂️

xの方程式 4+ (a+1)2x +1 +α+ 7 = 0 が異なる2つの正の解をもつよう な定数αの値の範囲を求めよ。 (ReAction 文字を置き換えたときは、 その文字の範囲を考えよ 例題177) 思考プロセス t=2^ とおく 4*+(a+1)2x+1+α+ 7 = 0 が 異なる2つの正の解をもつ t+2(a+1)t +α+ 7 = 0 が どのような解をもつか? 対応を考える 1つのtの値に1つのxの値が対応 例題179 との違い... f(t) =αの形にすると, 式が複雑になることに注意。 ... 解 4% + (a+1)2+1+α+7= 0 ・・・ ① とおく。 例題 2x = 174 = t とおくと, x > 0 より t>1であり, ① は t + 2 (a + 1)t +α+ 7 = 0 ... ② ここで, t = 2 を満たすx は, t>1であるtの値1つに 対して x>0であるxの値1つが存在する。 よって, xの方程式 ① が異なる2つの正の解をもつのは, tの2次方程式②が1より大きい異なる2つの解をもつ ときである。 y y=f(t)| 2にそろえ, 2 = t とおく。 y t=2* IA -(a+1) 2次方程式の解と係数の 関係 f(t) = f+2(a+1)t + α +7 とおくと, y=f(t) のグラフがt軸と t>1の範 囲で2点で交わるのは,次の [1]~[3] を満たすときである。 ○ 1 [1] f(t) = 0 の判別式をDとすると D> 0 D = (a+1)-(a+7) = a + α-6 4 +α-6>0より よって a <-3, 2 <a (a+3) (a-2) > 0 ③ [2] y=f(t)の軸が t>1の部分にある。 y=f(t) の軸は t = -(a+1) であるから -(a+1)>1 よって a<-2 [3] f(1) > 0 であるから f (1) = 3a+10 > 0 10 よって a> - ..⑤ 3 a+β = -2(a+1) aẞ = a+7 を利用して 判別式 D0 (a-1)+(-1)>0 (a-1)(-1)>0 からαの値の範囲を求め てもよい。 ② を t°+2t+7 = α(−2t-1) と分離して, y = t + 2t + 7 とy=α(-2t-1) が t>1で異なる2つの共 有点をもつようなαの値 の範囲を求めてもよい。 ⑤ より, 求めるαの値の範囲は 10 <a<-3 3 10 3 3 -2 2

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英語 高校生

この黄色いマーカーのとこの分構造を教えて欲しいです。

異議をとなえる 明治大文 significant five per cent. 2022年度英語 7 chalerghg T困難だがやりがいある always prefer print to ebooks. By 2016, that number had climbed a modest but 控えぬ The increased sales books) and their popularity with of younger people, demonstrate that old media is not just the province the old)/ 領域 3 The argument that printed books were becoming outdated and obsolete was by challenged not only by books' renewed popularity, but also by expert studies that pointed out the psychological Benefits enjoyed by people (who liked to read 動 a remedy for (イ) b.difficult writing) (in other words researchers suggested reading ( n all sorts of problems) (2013) the journal Science published a study that concluded that people who mostly read literary writing had a clearer appreciation breached other people's ways of thinking than those who tended to prefer popular bestsellers: The authors (②this study) discovered readers to be better (あ the emotions expressed faces on at understanding others' false beliefs when they had just read prizewinning short stories than when they had I read lighter more commercial writing: This experiment provided a new contribution to the familiar debate (on the difference between literary writing and popular bestsellers Bluzin 1 0 experiment suggested b/captivated (②E a printed book) remained a worthwhile (even in the digital age that finding time to be activity (C① many people) O 4 est The view that people the past read more were better readers is not ✓ and (historical evidence. It is true that print experienced a golden age between the rise D mass audiences: ( the eighteenth century (and the twentieth- a century triumph of the paperback Nonetheless, well before competition (from social media, only a finy minority (①volumes that were published ever found a ader(1 Instead of reading novels carefully, aristocrats had their hair curled reader ✓ ever while listening to a servant reading aloud Long before people compiled favorite songs or pieces of music on their computer or mobile phone, poetry lovers scissored pages apart to paste scraps of one collection onto the margins of another. Early bookstores sold fish, while books were also sold door-to-door by clothing salesmen. Authors back then debated in print, as strongly as today's content providers do online, whether the written work should be rented or sold, licensed or owned. In short, printed books gave birth to many of the capacities cs CamScanner でスキャン

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