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数学 高校生

数学Aの確率の問題です。 127の(2)がどうしても理解できません。 まず、なぜ式変形をして1+4-n/n(n+6)になるのから始まり、そこから下に関しては精講を読んでもわかりませんでした! 教えてください!よろしくお願いします!

基礎問 127 確率の最大値 Pet 白玉5個、赤玉n個の入っている袋がある. この袋の中から、 2個の玉を同時にとりだすとき, 白玉1個, 赤玉1個である確率 をnで表すことにする. このとき, 次の問いに答えよ.ただし, n≧1 とする. (1) n を求めよ. を最大にする n を求めよ. 精講 条件に文字定数nが入っていると, 確率はnの値によって変化する ので,最大値が存在する可能性があります。 確率の最大値の求め方 は一般に,関数の最大値の求め方とは違う考え方をします.それは、 変数が自然数の値をとることと確率 ≧0であることが理由です。この考え方は、 パターンとして頭に入れておかなければなりません. その考え方とは次のようなものです.いま, すべての自然数に対して > 0 のとき, ある自然数Nで, n≦N-1 のとき, すなわち, n≧Nのとき, が成りたてば,nで表されている確率は, OSNO Pn+1>1 Pn pn+1 <1 Pn P₁<P₂<<PN> ÞN+1>...... が成りたちます。だからn=Nで最大とわかります. * LODED Pn+1 と1の大小を比較すればよいのです. ここで, pn Pn+1>1 Pn+1-Pn>0 Pn ですから、 Pn+1- 0の大小を比較してもよいのですが、 確率の式という のは、ふつう積の形をしていますので,わった方が式が簡単になるのです. (1) pn= 20 pn+1. Pn (2) .. 5C₁*nC₁ n+5C2 = 参考 ポイント 演習問題 127 pn+1−1= Pn 2.5.n (n+5)(n+4) 10n (n+5)(n+4) (n+1)(n+4) n(n+6). 10 (n+1) (n+5)(n+4) (n+6)(n+5) 10n よって,n<4のとき, 解 ·X 4-n n(n+6) 4-n -=1+- 1² n(n+6) n+11 Pn n=4のとき, Ds=pa 答 : D₁<P₂<P3<Þ4=Þ5> P6> Þr>...... よって, n を最大にするnは, 4,5 n≧5のとき,P+1<1 Pn AnCr=- 207 18S n! r! (n=r)! Pn+1の形で1と大 pn 小を比較 <n(n+6)>0 だから 符号を調べるには分 子を調べればよい 確率の最大値は,わって1との大小比較 この式をかく方がわ かりやすい この考え方は確率以外でも ① 定義域が自然数 ②値域 > 0 をみたす関数であれば利用できます。 たとえば,f(n=n(n+3) などです. この関数は n=2で最大になりま 2" すので、各自やってみましょう. ある袋の中にn個の白玉が入っていて、そのうち5個に赤い印 がついている. その袋から, 5個の玉を同時にとりだしたとき 2 一個の玉に赤い印がついている確率をpとおく. ただし, n ≧8 と する.このとき、次の問いに答えよ. (1) n をnで表せ. (2) を最大にするnを求めよ。

未解決 回答数: 1
英語 中学生

教えてください!

1 関係代名詞 whose <所有格〉 区関係代名詞 whose は関係代名詞にかわる語が所有格のとき用いる。 先行詞が 「人」でも「人以外」でも用いる。 [人] I know the woman. The woman's name is Hiroko. 先行詞になる語句 所有格 (その女性の) 30 whose I know the woman whose name is Hiroko. 私は名前がヒロコであるその女性を知っています。 問 1.次の 内に,適当な関係代名詞を書きなさい。 (1) I know the house ( ) roof is red. (2) I know the teacher ) name is Ichiro. 問 2. 関係代名詞を用いて, 1つの文に書きかえなさい。 (1) Look at the mountain. The mountain's top is covered with snow. (2) Do you know the boy? His father works for a bank. 2 関係代名詞 that <主格・目的格) □関係代名詞 that は先行詞が 「人」でも「人以外」 でも使える。 alood art beerl 次の場合、関係代名詞は that が用いられることが多い。 ① 先行詞の名詞に最上級の形容詞がついているとき。 ②先行詞の名詞に下のような強調する言葉がついていると the first 「最初の 」, the very 「まさにその」, every 「すべての」, all 「すべての」, the only 「唯一の」, the last 「最後の」, the same 「同じ」など (2) Music is the only thing. 問 1.次の()内に、 適当な関係代名詞を入れなさい。 (1) He is the man ( ) I spoke to at the party yesterday. (2) He is the first man ( ) I saw yesterday. 問 2. 関係代名詞を用いて, 1つの文に書きかえなさい。 (1) This is the computer. My father bought it for me. I am interested in it. urknee

解決済み 回答数: 1
英語 高校生

一枚目 長文 二枚目 問題(ア) 三枚目 自分の答えand模範解答 付属の解説本が意味不明でした。解説お願いしたいです。

10 Life Reading 目標 20分 速読問題 次の英文を2.5分で読んで, 1. の問いに答えなさい。 Would you like to try to read a book that is 140 pages long every day! Many - are Japanese are surprised (2) to learn how long some American newspapers are. They a Slæom orll aneqsgewen to ancieev listipib ert asli orl not always 140 pages long, but they are usually at least 50 pages long. On Sundays 70198 ni olqooq odT C to 21697 0 1 qoq T some big city newspapers have hundreds of pages and *weigh almost a kilogram. gnibro biqs news, too. 37 There are lots of sections 5 (3) Of course, not everything in such a newspaper is news. m2 T raqaq zabavě s esi vis (1974-monib) 19m 16918 i 1996 about books, movies, travel, computers and hobbies, as well as star interviews and es, as well s boy arroqe bas zadintend comics in color. There are also many *advertisements, of course, but a lot of people ano ang m CECING OF COU vsbru² no,199sq ylisb niebimos atidhe bias Hold com bris flood, 25ñola bas find the advertisements very entertaining. Of course, the newspapers have a lot of he) {lind sdt ni snovievs ch the news Moky) zpililoq You may be surprised to find that (4)such large newspapers are (5)very cheap. They gaidyar are much cheaper than a newspaper in Japan. A large, heavy Sunday *edition of a vbodyas J Sunday edition of a Japanese newspaper. ding/ 4 weigh [wéi] : 重さが・・・である 11 edition [idífan] : (新聞の)… 版 1. smi ca ad te bear a newspaper in a big city may only cost about 350 yen, but it is 20 times bigger than the JR noilo92 smse sdt best a siqot amae ad juos at ziqot installib yasm tuds et 7 advertisement [ædvərtáizmənt]: 2 @ (171 words)

解決済み 回答数: 2
英語 高校生

一枚目 長文 二枚目 問題(ア) 三枚目 自分の答えand模範解答 付属の解説本が意味不明でした。解説お願いしたいです。

10 Life Reading 目標 20分 速読問題 次の英文を2.5分で読んで, 1. の問いに答えなさい。 Would you like to try to read a book that is 140 pages long every day! Many - are Japanese are surprised (2) to learn how long some American newspapers are. They a Slæom orll aneqsgewen to ancieev listipib ert asli orl not always 140 pages long, but they are usually at least 50 pages long. On Sundays 70198 ni olqooq odT C to 21697 0 1 qoq T some big city newspapers have hundreds of pages and *weigh almost a kilogram. gnibro biqs news, too. 37 There are lots of sections 5 (3) Of course, not everything in such a newspaper is news. m2 T raqaq zabavě s esi vis (1974-monib) 19m 16918 i 1996 about books, movies, travel, computers and hobbies, as well as star interviews and es, as well s boy arroqe bas zadintend comics in color. There are also many *advertisements, of course, but a lot of people ano ang m CECING OF COU vsbru² no,199sq ylisb niebimos atidhe bias Hold com bris flood, 25ñola bas find the advertisements very entertaining. Of course, the newspapers have a lot of he) {lind sdt ni snovievs ch the news Moky) zpililoq You may be surprised to find that (4)such large newspapers are (5)very cheap. They gaidyar are much cheaper than a newspaper in Japan. A large, heavy Sunday *edition of a vbodyas J Sunday edition of a Japanese newspaper. ding/ 4 weigh [wéi] : 重さが・・・である 11 edition [idífan] : (新聞の)… 版 1. smi ca ad te bear a newspaper in a big city may only cost about 350 yen, but it is 20 times bigger than the JR noilo92 smse sdt best a siqot amae ad juos at ziqot installib yasm tuds et 7 advertisement [ædvərtáizmənt]: 2 @ (171 words)

回答募集中 回答数: 0
英語 中学生

英語のリーディングの問題を、S V O C 、() 、→ などを書いていつも訳しています ՞ ՞ 文の構造をしっかり理解しようと思ってしているのですが、テストでだと時間的にやめた方が良いですか ?? 慣れてきたのか最初よりは書き込みも早くなったとは感じますが … ... 続きを読む

a a high school student in Japan> He is from Australia. He finds two of his friends, Hikari a (+"=> in their classroom and talks to them. of our S : Hi, Hikari, Takuma. What are you looking at? : Hi, John. We are looking at *results of a *survey about the school trip) O ↑ In the survey, 243 first-grade students(at our high school were asked the question: "Where you want to go on the school trip?" Look at this *graph. V : Oh, the most popular place is Okinawa. I understand that because we can swim in C beautiful sea and its culture is very interesting. Have you ever been to Okinawa? (1127 くどこ : Yes. I went there on an *elementary school trip and a family trip last year. My best me O s in Okinawa is *snorkeling in the sea. There were a lot of beautiful fish in the water, and S V excited when I saw them. I had a really good time during each of the trips. LEES くりつ) : I went there on the school trip when I was a second-grade student (at junior high s 12x During the trip, we didn't stay at a hotel. <+1>> : Oh, really? Where did you stay then? Sone houses くどこう : We visited some houses and stayed there. I stayed at Mr. Higa's house. He and his Cat=r=" were very kind and did many things for me. For example, they took me to some V places and made me some traditional dishes. I also had an experience (of taking care サトウキビ cane in their field. I had no chance to see sugar cane before coming to that field) S very interesting. Staying with Mr. Higa and his family is my best memory in Okinaw : Wow, you both enjoyed staying in Okinawa. I have become more interested in visi 動名詞 ↑ listening to your stories. 化現在完了形 S : I'm happy about that. If you visit Okinawa, you will like it very much, too. : Well, I've heard that a lot of students go to Kyoto or Nara on the school trip. But (Y" => S SV shows that only fifty students want to go there. I'm a little surprised about that. And V is more popular than Kyoto and Nara 最上 S : Look! Some foreign countries were chosen, too. And your country is the most them all) gift no : I'm happy about that. *Hawaii is also popular, right? 自然と同じくらい SV S V : Yes, it's as popular as Nara. A lot of Japanese people go there on their trips ev S V

解決済み 回答数: 1