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数学 高校生

(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

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英語 高校生

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

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