学年

質問の種類

数学 高校生

接線の単元です。接する⇔重解という記述が引っかかっています。2枚目の写真ではどうしてこの解き方を使っていないのか、と言うのがよくわかりません。

次のものを求めよ。 おける法線の方程式 三有点のうち,点 (2,-1/4) コ, f(a)) における法線の方程式 1 -(x-a) f'(a) と曲線の方程式を連立させて E ーる接線の傾きは =1 ある。 星式は -(x-2) 以外の点の座標 p.327 基本事項 y=f(x)/ YA 法線の傾きをmとすると mxf'(2)=-1 よってm=- 洗 = -0 ・法線 基本 例題 207 2曲線に接する直線 | 2つの放物線y=-x2, y=x2-2x+5の共通接線の方程式を求めよ。 指針 1つの直線が2つの曲線に同時に接するとき, この直線を2つの曲線の共通接線 いう。 ① 一方の曲線 y=f(x)上の点A(a, f(a)) における接線の方 程式を求める。 [2] ① で求めた接線が他方の曲線 y=g(x) と接する条件から, aの値を求める。 接する重解の利用。 他にも検討で示したような解法も考えられる。 y=-x2 に対して y'=-2x 解答よって,放物線y=-x2 上の点 (a, -α²) における接線の方程式は y-(-a²)=-2a(x-a) すなわちy=-2ax+a² ① この直線が放物線y=x2-2x+5に も接するための条件は、 2次方程式 x2-2x+5=-2ax+α² すなわち x2+2(a-1)x-a²+5=0 ② が重解をもつことであ D=0 る。ゆえに,②の判別式をDとすると D -=(a-1)²-1-(-a²+5)=2a²-2a-4-2(a+1)(a-2) ...... ...... 基本 204 重要 208 演習 231 接する V (a,-a²) 接する y=-x-x (a,-a²) y=g(x)\\ | 接線が求めやすい方 を指針の手順 ① y=f(x) とするとこ y=x²-2x+5y-f(a)=f'(a) よって ゆえに (a+1)(a-2)=0 a=-1, 2 この値を①に代入して、求める共通接線の方程式は y=2x+1,y=-4x+4 接する y=f 接する y=x2-2x+5 y=-2ax+α²

解決済み 回答数: 1
英語 高校生

英語の選択問題を解いてみたのですが、自信が無いのでどなたか教えてくださると嬉しいです。 特に[1]と[2]が分かりません。

[1] Hello, everyone. Today, I want to ( you had ( C ) sleep last night? Let's say, more than seven hours? Today's (d ) is going to (e effects of lack of sleep. 1. among 6. introduction A a 2. depend 7. many b a 2 a ) a common problem ( b ) university students, lack of sleep. How many of ) on the causes and 5 [2] Finishing your assignments, preparing for exams, partying, or checking your smartphone these are the common (a ) why students stay up late. I understand that these are important ( b ) of university life. But today, I want to (c ) you that sleep actually ( d ). We need enough sleep because sleep deprivation can (e ) seriously negative impacts on our health. 1. ask 6. matters 2. become 7. parts b 3. discuss 8. presentation 4 C 3. cause 8. questions C 4. enough 9. talk 4 C 4. convince 9. reasons 5. focus 10. to d 8 d [3] First, lack of sleep (a ) affects your physical health. Research has shown that sleep deprivation can impact the immune ( b ). Consequently, to fight infections becomes more difficult, and we become more likely to get sick after being exposed to a ( C ). Moreover, if you regularly follow a poor sleeping schedule, your risk of developing serious (d) conditions increases ( e ), such as obesity, heart disease, and diabetes. 1. medical 2. negatively 3. significantly 4. system b d 5. just 10. situations. 4 e 5. virus e 3 e 3

解決済み 回答数: 1
英語 高校生

Aの1,2,3はこれで合ってますか? 間違えていたら教えて下さい🙇‍♀️

2 Grammar Future with will, may, and might) 4.23 You can use will to give facts or predictions about the future. adol Looking ahead UNIT 12 Extra practice p. 151 To show you are not 100% sure about the future, you can use may and might. I'll be 65 in June. It'll be expensive to travel around Europe. The baby will keep us busy! It won't be easy to find a job. I'll = / will won't = will not I may go on for a master's degree. I might not be able to afford it. You can also use will with expressions like I guess, I think, maybe, and probably. We'll probably take some time off from work. Maybe we'll move to Arizona. Avoid will to talk about plans or decisions already made. Use the present continuous or be going to. I'm going to Europe next year. I'm going to visit Paris. (NOT I will go to Europe next year. I will visit Paris.) Common errors A Circle the correct options in the conversations below. Compare and practice in groups of three. 1. A What are you going to do at the end of this course? B. I'm not sure. I guess I take /I'll take another course. C I don't know. I'm going to / I may travel abroad with my brother. He thinks his classes might / can finish early this year, so we might / will be able to go in May. Don't use can for predictions. Use may or might. I may go away for vacation. (NOT I can go away for vacation.) 2. A Are your friends going away for vacation next summer? B Well, they're all going to do / will all do different things. One friend is going / will go to Istanbul. I'd love to go, too, but I don't know. I won't / I might not be able to afford it. C Four of my friends will / may be 21, so we're having have a big party. It's going to be fun. 3. A Are you going to look for a new job next year? B Actually, I just got a new job. I'll / I'm going to work for the local newspaper. How about you? C I don't know. I think I'm studying / I'll study for a certificate in nutrition. I mean, I'll / I may probably go back to school because I'm pretty sure I won't / might not get a job. Give your own answers. Who has interesting plans?

解決済み 回答数: 1