(4)の解説でなんで割ったら最小値が求められるのかわからないので教えて欲しいです!!

基礎問 256 第8章 ベクトル 165 四面体 (Ⅱ) 座標空間に2点A(2, 2, 3), B(4, 3, 5) をとり,ABを1辺と する正四面体 ABCD を考える. (1) AB, AB AC を求めよ。 (2) 辺AB をt (1-t) に内分する点をPとするとき,PC・PD |PC をt で表せ. △ (3) ∠CPD=0 とおくとき, coseをtで表せ。 (4) cose の最小値と,そのときのtの値を求めよ。 精講 (1) AとBしか与えられていないのに, AB AC が求まるのか?と 思った人は問題文の読み方が足りません。 「正四面体」と書いてあります. 正四面体とは,どのような立体 でしょうか. (2)164のポイントにあるように, 平面 PCD で切って平面の問題にいいか ます。 (3)空間でも, ベクトルのなす角の定義は同じです. 解答 正四面体だから (1) AB= (2,1,2) だから,20 |AB|=√4+1+4=3 また, △ABCは正三角形だから, ∠BAC= =2, |AC|=|AB|=3 :.AB.AC=|AB||AC|cos/5 3 1 9 =3.3. 2 2 (2) PC=AC-AP=AC-tAB PD=AD-AP=AD-tAB B △ACD, △ABDも正三角形だから AC·AD=AB·AD=AB·AC= 9 1-10 正四面体の性質 2 よって、PC・PD=912-9t+2 9 また,|PC|=|AC-tAB|=|AC|-2tAB・AC+AB 257 A 92-9t+9 (3)|PD|=|AD-tAB=92-9t+9 だから 正四面体だから (1) PC・PD 18t2-18t+9 cos = |PC|PD| 2(912-9t+9) 2t2-2t+1 2t2-2t+2 (4) cos0=1- 1 COS 212-2t+2 すべて等し距離 品 1 +- + 2 <わり算をすることで, 分子の次数を下げる 1 よって,t=1/2 のとき,最小値 1/3 ポイント 正四面体とは, 4つの面がすべて合同な正三角形であ る四面体 注 正三角すいと正四面体は異なります. 正三角すいとは, 右図のように, A 1つの面は正三角形, その他の面は, 合同な二等辺三角形であるような四面 体です. B 1-t 演習問題 165 ・PC・PD=(AC-AB) (AD-AB) =AC・AD-tAB・AC-tAB・AD+LAB 1 正四面体 ABCD の辺 AB, CD の中点をそれぞれ, M, Nとし, 線分 MN の中点を G, ∠AGB=0 とするとき, AB=2 として次の 問いに答えよ. (1) GA, GB を AB, AC, AD を用いて表せ. (2)|GA, GB GA・GB の値を求めよ. (3) cose の値を求めよ. このとき 第8章

全然わからないです😭 1問でも教えて頂けたら嬉しいです…🙏

Lesson 3. Palliative Care 部突破! いま最もアツく、最もイカ Medical treatment / Health STEP P 1 Read the Article Let's learn about palliative care, medical care that relieves pain, symptoms and stress caused by serious illness. 1) Palliative care, form of health care that seeks to improve the quality of life of patients with terminal disease through the prevention and relief of suffering. It is facilitated by the early identification of life-threatening disease and by the treatment of pain and disease- associated problems, including those that are physical, psychological, social, or spiritual in nature. As defined, palliative care begins at the point of diagnosis of terminal disease and can be delivered in a variety of health care settings. In general, it involves health and social care professionals working in hospitals, communities, hospices, and voluntary sectors. 2) Palliative care has been associated with many different terms, including terminal care, care of the dying, end-of-life care, and supportive care. However, these forms of care are not necessarily the same as palliative care. Likewise, palliative care is also sometimes described as hospice care. While hospice care does imply palliative care, it is specific to care provided near the end of life. In contrast, palliative care covers the duration of a patient's illness and, hence, may be delivered over the course of years. 3) Palliative care emphasizes three main principles: 1) A team-based approach is fundamental in managing distressing symptoms, such as pain, nausea, fatigue, and depression. It is also a necessary component in meeting the physical and psychosocial needs of the patient and his or her family. 2) Dying is a normal process. Symptom management is needed in order to help patients live life to the fullest until they die. 3) The synthesis of physical care with psychological and spiritual care fulfills a vital role in the overall care of the patient. 4) Palliative care is a global concern, and a steady rise in the number of people who are living longer with degenerative disease suggests that demand for palliative care services will increase in the are areas of intense. developments such Standards Framewo and Palliative Care Indian Association health care profes intended to help physical and psyc 5) In some place For example, the and has identifie framework is int days of life. Its communication, their families, a palliative c diagnosis duration: nausea H Log in to Watch th Hear resear the 2020 co

なんでこの式で角度が出るんですか？

OMLAB, ONIACである A ただし、(S)(3)にごり B ID A B ID (1)より OA⊥OBであるから, A SI 1 ∠ACB × 270° 2 =135°

この回路のVcdとIabの求めたいんですけど、回答は3つの閉路を取ってました。その時I1=I2=Jになる理由が分かりません。何故ですか？

N ZA lab b

合ってるか見てほしいです！

180 I used to spend so ( ) time watching TV. ①a lot ②a few much ④many 181 His house had ( ) furniture when I saw it. Da couple of ②few ③little not many 182 During the encore, the audience was so ( ) that they stood up. ⑪excite excited ③3 excitement ④exciting 183 You can have lessons when it is ( ) for you. ①convenient free ③available capable

答えが、2.3どちらも当てはまるような気がするんですけど、正しい答えってどっちなんですか？💦

League Selection Join us for an afternoon picnic with the coaches, players, and parents. Children meet the coaches for each team and practice hitting, throwing, and catching. At the end of the day, the players and parents choose their teams. Comments from Players and Their Parents The league is so much fun! My coach helped me play better, too! •There are 32 teams, so it's easy to find the one that's best for your child! •The playoffs are exciting! The top eight teams play in a tournament. • The coaches are kind and let every child play! The games are on Tuesday and Thursday nights, so they're convenient for families!

英検準一級のライティングです。 明日なので添削していただきたいです。 お願い致します。

7 S 2 Topic, should campanies be required to produce goods that are easy to recycle? Some people say that it is not necessary for companies be required to produce goods. - that are easy to recycle. On the other hand, 3 < others say not. I agree with the latter idea and have two 6 reasons why I think so. First of all, I will explain that from point of view of pollution. , Receatry, it is matter that a lot of things c. which can not recycle increase day by day. and the place where collect garbage is a becoming full in Japan. 12 Therefore, in order to make the world better, If it is important to recycle easily. 15 16 17 8) 20 21 22 Second of all, I will explain that from point of view of company profits. To clarify this, if the company use goods. that are easy to recycle, they can reduce costs to import a lot of materials. It will lead to increase Custmer's income. According to the reasons mentioned above, Companies should be required to produce 2 goods that are easy to recycle. 23 136

水色部分の訳し方が知りたいです

sports. // Esports also exhibit the same level of collaboration / as team sports such as soccer, baseball or volleyball / in which players work together on strategies to defeat the other team in the game. // 22 Finally,

このようにいえるのは何故ですか?？

=2(labl-ab)≥0 12 IZD2

中3です なぜkeepにsが付くのか教えて欲しいです！ お願いします💦

racticing ■ (2) 音楽は私を前向きな状態にしておきます。 Music Keeps esme positive.