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TOEIC・English Undergraduate

自分の回答と照らし合わせて確認したいので、答えがなにになるかどなたか教えてください。 解説もあると助かります。

5 A Matter of Taste Reading Passage 042 At the age of just 22, Jamie Oliver became well known across the UK as "The Naked Chef." He called himself this not because he cooked wearing no clothes, but because he wanted to simplify food preparation so that everybody could follow his recipes. He wanted to "strip down" the idea of cooking. Since then he has had numerous TV shows, published 50 many books, and has become a household name in the UK. Today, one of the activities Jamie Oliver is best known for is his great effort to improve the school dinners that children eat every day. One day, he visited the kitchen of a typical London secondary school, and he was shocked to see how much processed junk food the kids were given to eat each day. Fat and sugar levels were extremely high, and nutritional values very 10 low. The "turkey twizzler" became the symbol of these unhealthy meals: processed meat containing 21.2% fat and only 34% actual turkey. Oliver ran the school kitchen for one year and tried to show that it was possible to serve healthy meals on a limited budget—and that kids actually enjoyed eating them. His mission was to radically change the eating habits of children in that school, and across the country. 150 200 15 20 25 CULTIES 250 His project (the "Feed Me Better" campaign) has had some influence on school dinners in the UK. After watching the documentary Jamie's School Dinners, 271,677 people signed a petition calling for healthier school meals. This led the Prime Minister to agree to spend 280 million pounds (about 37 billion yen) on school dinners, to ban some junk food from school menus, and to create a School Food Trust to provide support and advice for people preparing school meals. Research, by the way, shows that children who stop eating sugary, fatty food and instead eat Oliver's school dinners are better behaved in class, and they get higher test 300 scores, too. 350 Of course, the project has had some problems. At first, many students (and even parents) resisted the removal of the junk food they were so used to. In one famous instance, some parents were passing local takeaway food to their children through the school fence. Also, schools that followed the plan for a while were often found to gradually drift back into bad habits. After all, it is easier and cheaper to just give the kids junk food. However, Oliver's efforts represent a positive start, and with obesity becoming such a huge problem (see Unit 4), 400 it's a very necessary start.

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Mathematics Undergraduate

数学のチャート式の問題です! 自分はこの2つの方程式がどっちも=0だったので2つの式の左辺同士をイコールで結び、共通解をαと置いて計算しました。それが、2枚目の写真のものです。ですが、それだと解答が間違っているようです。 なぜ自分の解答ではダメなのか、なぜチャート式の解... Read More

重要 例題 方程式の共通解 2つの2次方程式 2x2+kx+4=0, x2+x+k = 0 がただ1つの共通の実数 解をもつように, 定数kの値を定め、その共通解を求めよ。 CHART S OLUTION 方程式の解 共通解をメとおくる x=α が解⇔ x=α を代入して方程式が成り立つ もんだいは 2つの方程式の共通解を x=α とすると,それぞれの式にx=α を代入した 2a²+ka+4=0,a2+α+k=0 が成り立つ。これをα, kについての連立方程式 とみて解く。実数解という条件に注意。 解答 共通解を x =α とすると 2a²+ka+4=0 •••••• ・①, a²+a+k=0 ①②×2 から (k-2)α+4-2k=0 すなわち (k-2)a-2(k-2)=0 よって ゆえに [1] k=2 のとき 2つの方程式は, ともに x2+x+2=0 となる。 その判別式をDとすると (k-2)(a-2)=0 k=2 または α=2 D=12-4・1・2=-7 D<0であり,実数解をもたないから, k = 2 は適さない。 [2] α=2 のとき ②から 22+2+k=0 このとき2つの方程式は 2x2-6x+4=0 ゆえに k=-6 ...... (2) 基本 75 ...... ・①', x2+x-6=0 となり,①'の解はx=1, 2 ②' の解はx=2, -3 よって,確かにただ1つの共通解 x=2をもつ。 [1],[2] から k=-6, 共通解はx=2 x=α を代入した ① と ②の連立方程式を解く。 α² の項を消す。 共通の実数解が存在する ための必要条件であるか ら,逆を調べ十分条件で あることを確かめる。 ←ax²+bx+c=0 の判別 式は D=62-4ac 2(x-1)(x-2)=0, (x-2)(x+3)=0 (INFORMATION この例題の場合,連立方程式 ① ② を解くために,次数を下げる方針で α2 の項を消 去したが,この方針がいつも最も有効とは限らない。 下の PRACTICE 79 の場合は,定数項を消去する方針の方が有効である。 PRACTICE... 79 ④ の方程式ター(k-3)x+5k=0,x+(k-2)x-5k=0がただ1つの共通解をもつ ように定数kの値を定め、その共通解を求めよ。 2020vi S

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