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数学 高校生

an≠0であることを示すのはなぜですか?また、その示し方を解説していただきたいです🙏🏻

例題 日本 37ant point 型の漸化式 anti-pata 469 an an+1= 4an-1 '5' によって定められる数列 (an) の一般項を求めよ。 00000 [類 早稲田大) 基本36 重要46 指針+2 2 anのように,分子がan の項だけの分数形の漸化式の解法の手順は panta 漸化式の両辺の逆数をとると an an+1 an -=bm とおくと b+1=p+qbm →ba+1= Oba+▲ の形に帰着。 464 基本例題34と同様にして一般項が求められる。 また、逆数を考えるために, a,キ(n≧1) であることを示しておく。 CHART 漸化式 +1= an panta 両辺の逆数をとる an a+1=4a-1 ・・① とする。 解答 ① において, an+1=0とすると α = 0 であるから,an=00から10 となるn があると仮定すると anan2==α1=0 ところがα= 1/32 (0)であるから,これは矛盾。 これから20 以後これを繰り返す。 よって、 すべての自然数nについて α0である。 ①の両辺の逆数をとると 1 =4- an+1 an -=bm とおくと b1=4-bm 0 これを変形すると また ba+1-2=-(b-2) b-2=1-2=5-2=3 a₁ 逆数をとるための十分条 件。 14a-1 an+1 特性方程式 a=4-a5 a-2 4化式数列 ゆえに、数列{bm-2}は初項3,公比-1の等比数列で b2=(-1) すなわち bm=3・(-1)"'+2 したがって an 1 == 1 bn3(-1)"'+2 16.- / という式の形か an 5 640

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英語 中学生

添削お願いします🙇🏻‍♀️՞ 写真は左から、原文、問題、自分の解答です。 模範解答は、 D.Why don't you ask my mother and grand mother? E.They will tell you more about my red kimono... 続きを読む

(Nana is showing Kate a photo at home.) Kate: You are wearing a red kimono in this photo. Nana: Thank you. My mother took it at my uncle's wedding. Kate: The flower pattern on your kimono is amazing. Nana: That's true. It's my family's precious kimono. Kate: Why is the kimono precious? Nana: Actually, is bought my grandmother I this the kimono ] for my mother thirty years ago. Kate: Oh, you used your mother's kimono. Nana: Yes, but she gave it to me last year. So the kimono is ( @). Kate: Why did your mother give it to you? Nana: This red kimono has long sleeves. She thinks this kind of kimono is for young people, so she doesn't wear it now. Kate: I have a ( ℗ ) experience. My mother has a nice dress in her closet, but she doesn't wear it. I always wear it when I go to birthday parties. Nana: I'm sure your friends like the dress. Kate: Thanks. When I wear it, ⠀ Nana: : The designs of old clothes are different from the new ones, right? み Kate: Yes! I think wearing used clothes is fun. ( © ), wearing other people's clothes isn't easy because of the size. Actually, my mother's dress was large for me, so she adjusted it. Who adjusted your kimono? Nana: B Sonimom vis ns diwalls of WH Kimono has a simple shape, so it can be used easily by different people. Kate: Interesting. Kimono is not only beautiful but also functional. Nana: Right, so I love kimono. I'm glad to give my red kimono a new life. Kate: C Nana: If I wear my red kimono, it will have more chances to get out of the closet like your mother's dress. Kate: That's a good idea to use the kimono again. smozgnilos ayoung H Nana: I'll wear it on special days!

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