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Mathematics Senior High

赤線を引いたところがわからないです。(i)と(ii)までは分かります!

152 第2章 2次関数 Think 例題 77 **** HIERON 解の存在範囲(6) 2次方程式xー(a+2)x-a+1=0 が異なる2つの実数解をもち、そ 2の範囲にあるような定数aのとりう のうちの少なくとも1つが0<x<2 る値の範囲を求めよ . [考え方 解答 「2次方程式f(x)=0 の解の少なくとも1つが0<x<2の範囲にある」 は,次の3 つの場合に分けて考える. The story to (i) 2つの解がともに0<x<2の範囲にある場合(例題 70参照) ( 76 参照) 2つの解のうち一方のみが0<x<2の範囲にある場合(例題 x=0 や x=2 が2次方程式(x)=0 の解の場合は,それぞれの他の解は 0<x<2の範囲に存在するか (例題 76 参照) y=f(x)=x2-(a+2)x-a +1 とおくと, s(x)=(x-a + ²)² ²+8a a+2\² 4 2 より, y=f(x)のグラフは下に凸の放物線で, 軸が直線x=a+2, となる. 頂点のy座標がy=-4 .656 0> (²4)(C— DA) がともに0<x<2にある場合 a²+8a>0 (頂点のy座標) <0より, よって, α(a+8) > 0 から, a<-8,0<a a+2 2 ANTAR ***@ 軸 x=- が0<x<2の範囲にあるから, a+2 0<a <2 2 よって,0<a+2<4 より と -2 <a<2 (0) = -α+1>0 より となる。 a<1 ...... a²+8a ②以外の共有点 (2)=4-2(a+2)-a+1=-3a+1>0 より ( 330) 3 Buf ①~④を同時に満たすaの値の範囲は、0<a</1/3 (ii) 2つの解のうち一方のみが 0<x<2にあり, 一方が x<0,2<xにある場合 原点を中心にしてソー f(0)f(2)<0より、 拡大 (よって, (a-1)(3a-1)<0より, 1/3<a<1 soms (i) は例題 70 を参照 a²+8a -<0 4 の両辺に4を掛け る. (3 () (ア) (0)=0 の場合の図際は船であるという、 f(0)=-α+1=0 とすると, a=1 (-a+1)(-3a+1) <00 100- Focus のク参照一個に a= 注 (Ⅱ), () は例題76を 他方の図 E このとき f(x)=x2-3x=x(x-3) より, f(x)=0の解はx=0, 3 となり, 0<x<2に解をもたない. HOMO 13181

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English Senior High

問1(B) 答えは4ですが、2がダメなのは何故ですか? it was too fast で トーマスがフェンスを登るのが速かった になるので、2でもいいと思いました。 (c)答えは2ですが、驚いて助けたという意味で3もありなのではと思いました。

UNIT J 15 出題データ ■ワード数: 354 words ■難易度 : 超基礎 ●解答と解説:本冊 p.68~79 ■目標解答時間: 20分 kmon yitirbame 次の英文を読み、後の問いに答えなさい。 al UNIT 5 But ( D ) the zoo worker arrived, a gorilla went over to Thomas. It was Binti Jua, an eight-year-old mother gorilla. She had her baby gorilla on her back. With one "arm" she picked up the little boy. She carried him carefully over to a door, walking on 25 three legs. There she put Thomas down so a zoo worker could get him. mart qisilbin, 70100) It was a hot summer day in Chicago. The Kemper family decided it was a good day to go to the Brookfield Zoo. Janet and Kevin Kemper had two children: Thomas, 3, and Sally, 6 months. 30 Thomas loved going to the zoo. He liked watching all the animals, 5 but he especially loved the gorillas. The Kempers went straight to the gorilla exhibit. There were six adult gorillas and a three-month-old baby gorilla. In the Brookfield Zoo, the animals are not in cages. They are in large areas dug out of the ground. These areas have fences around 10 (1) them so the animals cannot get out and people cannot fall in. But three-year-old boys ( A ). While the Kempers were watching the gorillas, little Sally started to cry. Kevin took her from Janet, and Janet looked in her bag for a bottle of juice. In those few seconds, Thomas climbed up the fence. A woman saw him and shouted, "Stop him!" A tall man reached up to get him, but it was too (B). Thomas fell down the other side of the fence. He fell 18 feet onto the hard concrete floor. (2) He lay very still, with blood on his head. Janet and Kevin shouted for (C). People crowded around the fence, and someone ran to get 20 a zoo worker. Janet and Kevin ran to the door, too. Thomas was badly hurt and had to go to the hospital, but after a few days he was better. The story was on the evening news in Chicago. Some people cheered and others cried when they heard it. But many of them thought about that mother gorilla and asked themselves, "What is she doing in a zoo? What is the difference between a gorilla and me?" trid, jun but entre e *[*] the gorilla exhibit show ■設問■ 1. (A)~(D) に入れるのに最も適当なものをそれぞれ①〜 ④ の中から1つ選んで マークしなさい。 (A) 1 like to take care of animals 2 cry when they see the gorillas 3 are good climbers 4 are interested in watching the animals early (2) fast 2 help 2 though (B) (C) 1 cry (D) before 3 heavy 3 surprise 3 if late 4 the gorillas 4 until 17

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