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数学 高校生

高校数学Cベクトルの問題です。(1)の問題で、①の式からなぜ点線部の答えが出せるのかがわかりません。1/2ベクトルcから辺BCの中点を通ることが導けるのはわかるのですが、1+k/6ベクトルaからなぜ直線ABに平行な直線だとわかるのでしょうか。お願いします🙇‍♀️

15S, 10S となる. S=12S+8S=20S S2=10S S₁=15S より、 22 5 S.- (S)- 9 8S B Q C Si S₁ = 159 (31/3)=1/15 となる, S: S: S = 20S : 10S : 15S=4:2:3 △ABC があり。 実数kに対して、点PがPÃ +2P+3PC=kAB を満たすものとする。 次の問いに答えよ、 (1)kが実数全体を動くとき、点Pの軌跡を求めよ. (2) 点PがABCの内部にあるようなkの値の範囲を求めよ。 (1)点Bを基点とし, BA=a, BC=c, BP=♪ とすると, PA+2PB+3PC=kABより、 HA a-p)+2(-p)+3(c-p)=k(-a) A 6p=3c+(1+ka b=1/2+1+k² ...... 6 したがって、点Pの軌跡は,辺BCの中点 D を通り、 直線ABに平行な直線である。 (2)点Pの軌跡となる直線と辺 AC の交点をEとすると, AB//ED, D はBCの中点より, DE:BA=1:2, DE=BA 点Pが線分DE上(端点は除く)にあるとき, △ABC A 1kを含まない部分(動かない)と kを含む部分(動く) に分ける。 7-80 AJA BD KE の内部にあるから、①より, これを解いて, -1<k<2 0<1+k\/\ C kが実数全体を動くので、点 の軌跡は図の直線 DE であ 44

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英語 高校生

下線部(4)に関して、この質問に込められているDaveの気持ちを基本後で説明しなさい に対して 申し訳なさだと思ったんですけどこれってどんな意味があるんですか

4 20 Chapter 1 英文を読んで、 設問に答えなさい。 物語 271 words Time: 35 minutes Ted had a son, but his son had no mother. Ted and his seven-year-old A-1 son, Dave, lived alone. Ted was not very rich, so he had to work hard every day. One evening, Ted was driving home after his hard work. He was very 5 tired, but he loved his son. "(A) Dave must be feeling lonely now. I have to go home as soon as possible." He hurried home, but he came back home at nine o'clock. Dave was still awake when he saw his father, and said, "Dad, how much do you make an 時きゅうないとどうなの? 10 hour?" 息子 15 Ted got angry at his son. He was not making enough money for their living. And he was too tired to stay calm "Why do you ask (1)such a silly question when I come home from hard work? I make twenty dollars an hour. Is that good enough for you?" "I'm sorry, Dad. But... (B) will you give me ten dollars?" "Another silly question! Just go to bed and sleep! Right now!" A-2 After Dave went to his room, Ted sat down on his sofa and had a drink. (2)He came to himself again, and thought he was wrong to his son. He went 自分自身のうに into Dave's room. fr 理性をとりどす. "I'm sorry, my son. I didn't want to get angry with you. Here's your ten dollars." A-3 "Thank you, Dad!" 25 Dave got up and opened his treasure box. He had another ten dollars in it. When Ted saw this, (3)he got angry again. "Why do you want another ten dollars? You already have ten dollars!" But Dave asked, watching his Dad's eyes, "(4)Dad, can I buy your one hour with these twenty dollars?" come to oneself. begin acting and thinking like one's normal self A-4 「速読」 1. x >

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