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数学 高校生

この問題で(iii)の条件がなぜ必要なのか教えていただきたいです🥲よろしくお願いします🙏

imagine ! ©Disney KCL 142 第2章 2次関数 Think 例題 69 解の存在範囲(1) ***** 2次方程式 x2ax+3a=0 の異なる2つの実数解が,ともに2より 大きくなるような定数αの値の範囲を求めよ. [考え方 このような2次方程式の解の存在範囲を求めるときは,まず y=f(x)=x2-2ax+3a とおいて考える. 2次方程式 f(x) =0 の実数解は, 2次関数 y=f(x) のグラフとx軸との共有点のx座標である。このこ とに着目して, 「異なる2つの実数解が, ともに2よ り大きくなる」場合のグラフはどうなるかを考える。 2- 解答 y=f(x)=x-2ax+3a とおくと, f(x)=x2-2ax+3a =(x-a)2-a²+3a (東京工科大・改) (2,F(2) x=2 x=a a y=f(x) を平均 より,y=f(x)のグラフは,下に凸の放物線で, 軸が直線 x=α, 頂点が点 (a, -d+3a) となる. する. (S)01 ||x=2x=a f(x) =0 の異なる2つの実数解 が、ともに2より大きくなるのは, (2,2 y=f(x)のグラフが右の図のように なるときである. a 48 よって, 求める条件は, (i) (頂点のy座標) < 0 (ii) 軸が直線 x= 2 より右側 (iii) ƒ (2)>0 である. (i) -a²+3a<0 a²-3a>0 a(a-3)>0 より a <0, 3<a......① (ii) a>2 ② (iii) f(2)=4-4a+3a>0 0(1-3)(+)- RMO 0-1-+x(-) 910=0 1-3)= 頂点,軸, f (2) 0 に着目する. (i)は,判別式 D> より, 4 +20 L=(-a)-30 の両辺に =a2-3a>0 としてもよい より a<4 よって,①~③より, (3) 3<a<4 (3 数直線上で共通 (2 を確かめる。 3 4 a Focus 解の存在範囲の問題 (異なる2つの実数解が より大きい)は、頂点(判別 練習

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英語 高校生

この英文から、なぜ筆者のプランは毎月100ドル以上かかったと言えないのか教えてほしいです

B You are a college student going to study in the US and need travel insurance. You find this review of an insurance plan written by a female international student who studied in the US for six months. 0 There are many things to consider before traveling abroad: pack appropriate clothes, prepare your travel expenses, and don't forget medication (if necessary). Also, you should purchase travel insurance. Imam gavo 0012 1ovo od 1200 sla When I studied at Fairville University in California, I bought travel insurance from TravSafer International. I signed up online in less than 15 minutes and was immediately covered. They accept any form of payment, usually on a monthly basis. There were three plans. All plans include a one-time health check-up. gisinal The Premium Plan is $100/month. The plan provides 24-hour medical support through a smartphone app and telephone service. Immediate financial support will be authorized if you need to stay in a hospital. It had the 24-hour telephone The Standard Plan worked best for me. assistance and included a weekly email with tips for staying healthy in a foreign country. It wasn't cheap: $75/month. However, it was nice to get the optional 15% discount because I paid for six months of coverage in advance. If your budget is limited, you can choose the Economy Plan, which is $25/month. It has the 24-hour telephone support like the other plans but only covers emergency care. Also, they can arrange a taxi to a hospital at a reduced cost if considered necessary by the support center. I never got sick or hurt, so I thought it was a waste of money to get insurance. Then my friend from Brazil broke his leg while playing soccer and had to spend a few days in a hospital. He had chosen the Premium Plan and it covered everything! I realized how important insurance is-you know that you will be supported when you are in trouble.

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