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数学 高校生

この問題の解き方?っていうか言ってる意味がよくわからなくて解き方教えて欲しいです😭

ev 紹 (例題) 29 重複組合せの基本 次の問いに答えよ。 ただし, 含まれない数字や文字があってもよい。 とき、作られる組の総数を求めよ。 00000 (1) 1, 2, 3, 4 の4個の数字から重複を許して3個の数字を取り出す。 この (2) x, y, zの3種類の文字から作られる8次の項は何通りできるか。 & SOLUTION CHART L 重複組合せ ○と仕切りの活用 p.294 基本事項 3 と間違いやすい。 次のように,○と仕切りによる順列として考えた方が確実である。 (1) 異なる4個の数字から重複を許して3個の数字を取り出す。 p.294 基本事項 3 で示した Hr = n+r-1Cr を直ちに使用してもよいが、慣れないうちは 3個の○と3個の仕切りの順列 → 例えば〇〇〇|| 1 2 3 4 1 2 3 4 は11個 22個を表す。 〇〇〇は2が1個 31個 41個を表す。 (2)異なる3個の文字から重複を許して 8個の文字を取り出す。 8個の○と2個の仕切り」の順列 例えば〇〇〇 x y z 8次の項xyz を表す。 一〇〇〇〇はxを3個, yを1個, zを4個取った場合で, 303 1章 3 組合せ 新訓 式 答 (1)3個の○と3個のの順列の総数が求める場合の数とな 6.5.4 るから 6C3= -=20 (通り) 3.2.1 求める組の総数は,4種類の数字から重複を許して3 (+S) ++ 個取り出す組合せの総数に等しいから 4H3=4+3-1C3=6C3=20 (通り)FOX (2)8個の○と2個のの順列の総数が求める場合の数とな るから 10.9 10C8=10C2= -=45 (通り) 2.1 3Hs=3+8−1Cg=10C8=10C2=45 (通り) ← 6個の場所から○を置 く3個の場所を選ぶ総 数。これは,同じものを 含む順列の総数であり 6! 3!3! -=20 でもよい。 ←nHr=n+r-1Cr ← 10! -=45 でもよい。 2!8! PRACTICE 29 3 ③ (1)8個のりんごをA,B,C,D の 4 つの袋に分ける方法は何通りあるか。ただし, 1個も入れない袋があってもよいものとする。 (2)(x+y+z)の展開式の異なる項の数を求めよ。

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英語 中学生

英文読解です。左が文章、右が問題です。写真が見にくいかもしれませんが、お願いします。

How Much Is a Tree Worth? It is easy to measure the value of most things that people own. If you want to sell your house or car, for example, an expert will be able to tell you how much money it is worth. However, it's much harder to decide how much things in nature are worth. What is the value, for example, of a tree? One way to measure the value of a tree could simply be in terms of how much money could be made from cutting it down and selling the wood. A tree might be worth more, however, if it isn't cut down. In the case of a fruit tree, for example, we would have to ask how much money could be made by selling the fruit that the tree produces over its lifetime. Furthermore, what about the seeds that tree produces that can grow into new trees that will produce their own fruit? Do these elements add to the value of the original tree? In assessing its value, we might also look beyond the tree itself to the other creatures that live in it. For example, insects, birds, and other animals could not survive without the tree. These creatures use the tree for both food and shelter. Does the fact that the tree supports all these other lives add to the value of the tree itself? Trees also offer non-monetary benefits to people. For example, a tree gives us shelter on a sunny day or provides refuge from heavy rain. How much are these things worth? And what about the beauty of trees that can calm us when we are feeling stressed and that even inspires poetry. How do these kinds of benefits add to the value of the tree? If placing a value on a tree is such a difficult task, placing a value on nature itself is likely impossible. The natural world is an irreplaceable wonder that not only provides humans with many of our basic needs but also inspires us. How do we place value on such a resource? Before You Read Vocabulary CANTON Look at the definitions below. Can you find words that match the definition in the word grid? Some letters have been given to you as clues. Match the words with their definitions below. Definitions worth (n) The importance of an item Reading for Gist Scan the article "How Much Is a Tree Worth?". How many paragraphs are there? Now match each paragraph with the best heading below. There are more headings than you will need. Paragraph 1. Paragraph 2. Paragraph 3. Paragraph 4 produce (v) A person with special skills/knowledge about a subject Paragraph 5. Paragraph 6. value (n) • How much money something should cost creature (n) A small, hard object produced by a plant from which a new plant can grow seed (n) To make or create something Trees add to the beauty of nature. It's impossible to say how much nature itself is worth. How much is a tree worth if we don't cut it down? Different trees offer different kinds of benefits to people. Do the non-monetary benefits that a tree offers add to its value? . Can a tree's value be measured in terms of the wood it provides? Deciding the value of things in nature is a difficult task. Do the creatures that live in a tree add to its value? Reading for Detail Now read the article again in more detail and answer the questions below. According to the article, are the following statements true (T) or false (F)? Underline the part of the text in which you find the answer. monetary (adj) . An animal, especially a nonhuman a. An expert can easily tell you the value of a tree. T/F b. The fruits and seeds that a tree produces might add to its value. T/F c. Many creatures need trees in order to be able to live. T/F d. Trees are only important in terms of the money that they are worth. T/F e. It would be difficult to say how much money nature is worth. T/F expert (n) . Of or relating to money 75 Unit 5: Economics JPREP Empower Vol.76

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