学年

教科

質問の種類

数学 高校生

2で何回割り切れるか、なので2で割った商を調べるのはわかるんですが、なぜ2の二乗、2の3乗、2の4乗も考える必要があるんですか?

115 素因数の個数 基本 例題 115 (1) 20! を計算した結果は, 2で何回割り切れるか。 (2) 25! を計算すると, 末尾には 0 が連続して何個並ぶか。 [類 法政大 ] 13 第1章でも学習したが, 1からnまでの自然数の積1・2・3···.... (n-1) n をnの階乗と ger+p'as (1) AT いい, n! で表す。 (1) 1×2×3×・・・・・・×20の中に素因数2が何個含まれるか, ということがポイント。 25 32 > 20 であるから, 2, 22, 23 24の倍数の個数を考える。 (2) 25! に 10 が何個含まれるか, ということがわかればよい。 ここで, 10=2×5 であるが, 25! には素因数2の方が素因数5より多く含まれる。 したがって, 末尾に並ぶ0の個数は, 素因数5 の個数に一致する。 CHART 末尾に連続して並ぶ 0の個数 素因数5の個数がポイント Sapon で 解答 (1) 20! が 2で割り切れる回数は, 20! を素因数分解したときの 素因数2の個数に一致する。 1から 20 までの自然数のうち, 2の倍数の個数は20を2で割った商 についていく 10 といわ 22の倍数の個数は, 20 を2で割った ったとき 商で 5 About to... 2° の倍数の個数は20を2で割った 商で SOBOTE 08 249 250 22: 23: 24: 基本109 2:00 2 4 6 8 10 12 14 16 18 20 30121 素因数2は2の倍数だけが もつ。 483 ○・・・10個 〇・・・ 5個 2個 1個 ani 4章 2 2の倍数の個数は20を24で割った商で 注意 1からnまでの整数の うち の倍数の個数は,n 20<25 であるから,2"(n≧5の倍数はない。々で割った商に等しい(n. よって,素因数2の個数は、全部で 10+5+2+1=18(個) したがって 20! は2で18回割り切れる。 は自然数 25! を素因数 17 約数と倍数、最大公約数と最小公倍数 の

解決済み 回答数: 2
英語 高校生

共通テストのリーディングの問題で時系列的な問題があるのですが、何回やっても正解できません、 誰か教えて欲しいです。

B You found the following message on a personal blog written by an exchange student at your school. Save Our Park! Wednesday, April 21, 2021 Vera Sherman First, thank you for visiting my blog. Today I'm writing about something very close to my heart. I hope everyone in town has had a chance to spend some time at Kaneko Park. It is a lovely place, and it's easy to walk to from our school. As it is springtime, the park is currently full of blooming trees, singing birds, and people enjoying the outdoors. Some creative students even built little squirrel houses for the animals to live in. Unfortunately, however, we need to do more to help clean up our wonderful local park. One month ago, I was taking pictures of the flowers near the pond. When I looked at the pictures at home, I noticed some garbage in the background. I spoke to Mr. Tanaka, the city official who is in charge of the park. He told me that sometimes students eat fast food and leave packaging on the ground. He said that in the past he had asked students to clean up after themselves but very few students had actually done as he asked. Because students were a big part of the problem, I felt I should take some responsibility in trying to sort out this problem. I put up flyers explaining the situation and asking for students to help after school. A small group came out, but we were not well prepared. We didn't have enough trash bags, and we did not have a clear plan for cleaning up. I went back to Mr. Tanaka, and he promised me that next time we went to the park, the city would provide trash bags and maps of locations to clean. Now we are ready to make a difference. Maybe it doesn't seem fun to spend your time picking up trash, but please consider helping. We will be meeting outside the front gate of the park at 10 a.m. this Saturday. Please try to arrive by 10 a.m. as we will be starting the litter pick straight away. Let's all help clean up our beautiful park!

解決済み 回答数: 2