学年

質問の種類

数学 高校生

(1)で判別式Dの計算方法を教えてください🙇🏻‍♀️‪‪ マイナスをどう処理していいかが分かりません…。

32 女子 練習(1) 不等式2x≧kx-4の解がすべての実数であるような定数kの値の範囲を求めよ。 ②115(2) すべての実数xに対して,不等式 ax2+x-1)<x+xが成り立つような,定数αの値の範 囲を求めよ。 (1) 不等式を変形すると x2-(k+2)x+4≧0 [ (1) 金沢工大 f(x)=x²-(k+2)x+4 とすると, y=f(x) のグラフは下に凸 ←f(x)のx2の係数は正 の放物線である。 よって、不等式f(x)≧0の解がすべての実数であるための条件 は,y=f(x) のグラフがx軸と共有点をもたない,または,x 軸と接することである。 であるから,下に凸。 ゆえに,2次方程式 f(x)=0 の判別式をDとすると, 求める条 件は D≦0 D={-(k+2)}-4・1・4=(k+2+4)(k+2-4) =(k+6)(k-2) ←D <0とすると誤り! D≦0 の “S” は,グラフ がx軸と共有点をもた ない,または,x軸と接 (k+6)(k-2)≦0拌するための条件である。) であるから, D≦0 より よって -6≤k≤2 (2) 不等式を変形すると [1] α-1=0 すなわち a=1のとき A-1-1-1-((1+))=0 (a-1)x2+(a-1)x-a<0...... ① ① は 0.x2+0x-1<0となり,これはすべての実数xにつ いて成り立つ。 [2] α-10 すなわち α=1のとき 04(1) >I ①の左辺を f(x) とすると, y=f(x) のグラフは放物線であ る。よって, すべての実数xに対してf(x) <0 が成り立つた めの条件は,y=f(x) のグラフが上に凸の放物線であり, x 軸と共有点をもたないことである。 ゆえに, 2次方程式 f(x) =0の判別式をDとすると, 求める 条件は a-1 < 0 かつ D<0 D=(a-1)-4(a-1)(-a)=(a-1){(a-1)+4a) =(5a-1)(a-1) 1=0 のとき, ① の 左辺は2次式ではない。 0=1 (S) ←このとき,グラフは常 にy < 0 の部分にある。 ←a-1>0 とすると, y=f(x)のグラフは下に 凸の放物線となり、 f(x) の値はいくらでも 大きくなるから、常に x)(f(x)<0が成り立つこと であるから, D<0 より (5a-1)(a-1)<0 3<0 よって// <a 言くく (8- はない。 1 a-1 < 0 すなわちα<1との共通範囲は <a<1 marc 5 [1],[2] から,求めるαの値の範囲は / <a≦1 5

解決済み 回答数: 1
英語 高校生

投げやりです。すいません。英語皆無なので代行してください。

【必答問題 5 日常使う物のデザインをする際には標準化 (standardization) という方法がある。 という内容に続く次の英文を読んで、あとの問いに答えよ。(配点44) If we examine the history of advances in all technological fields, we see that some improvements come naturally through the technology itself, while others come through standardization. The early history of the automobile is a good example. The first cars were very difficult to operate. They required strength and skill beyond the abilities of many. Some problems were solved through automation. Other aspects of cars and driving were standardized through the long process of international standards committees: . On which side of the road to drive (constant within countries) country, but variable across On which side f the car the driver sits (depends upon which side of the road the car is driven) -The (2) of essential components: steering wheel, brake, clutch, and accelerator (the same, whether on the left- or right-hand side of the car) Standardization is one type of cultural constraint. With standardization, once you have learned to drive one car, you feel confident that you can drive any car, anyplace in the world. Standardization provides a major breakthrough in usability. I have enough friends on national and international standards committees to realize that the process f determining an internationally accepted standard is laborious. Even when all members agree on the merits of standardization, the task of selecting standards becomes a long, political issue. A small company can standardize its products without too much difficulty, but it is much more difficult for an industrial, national, or international body to agree to standards. There even exists a standardized procedure for establishing national and international standards. organizations works on standards. First, a set of national and international Then when a new standard is proposed, it must work its way through each organization's approval process. Standards are usually the result of a *compromise among the various competing positions, which can often be an inferior compromise. Sometimes the answer is to agree on (4 ). Look at the existence I both metric and *English units; of left-hand- and 18 right-hand-drive automobiles. There are several international standards for the *voltages and *frequencies of electricity, and several different kinds of electrical plugs and sockets- which cannot interchanged. With all these difficulties and with the continual advances in technology, are standards really necessary? Yes, they are. Take the everyday, clock. It's standardized. Consider how much trouble you would have telling time with a backward clock, where the hands revolved "counterclockwise." A few such clocks exist, primarily as humorous conversation pieces. When a clock truly violates standards, such as (the one in Figure 1, it is difficult to determine what time is being displayed. Why? The logic behind the time display is identical to that of conventional clocks: there are only two differences - the hands move in the opposite direction (counterclockwise) and the location of "12," usually at the top, has been moved. This clock is just as logical as the standard one. It. bothers us because we have standardized on a different scheme, on the very definition of the term clockwise. Without such standardization, clock reading would be more difficult: you'd always have to figure out the "mapping. E) compromise *metric メートル法の *English units イギリスの計量法(ヤードボンド法) *frequencies of electricity 電気の周波数 voltages E *mapping 対応づけ (2つのものの間の関係を意味する専門用語) 問1 下線部(1)の内容を、 同じ段落の自動車の例に基づいて30字以内の日本語で答えよ。た だし、句読点も字数に数える。 問2 本文中の空所 (2) に入る語として最も適当なものを、次のア~エのうちから一つ 選び 記号で答えよ。 7 color イ location ウ price I sight (239) 問3 第2パラグラフ (Standardization is one type of ...) について 次の Question に対す る Answer となるように、空所に入れるのに最も適当なものを,次のア~エのうちから一 つ選び、 記号で答えよ。 Question: What is "a major breakthrough in usability" provided by standardization? Answer Because of standardization, you ( device of the same kind all over the world. 7 can apply what you have learned to イ can make cannot produce I cannot use what you have learned when using 問7 下線部(5)が表す図 (Figure 1)として最も適当なものを、次のア~エのうちから一つ選 び記号で答えよ。 11 12 1 12 ) any machine or 10 2 10% 9 3 1 5 6 問4 下線部(3)の示す内容を, 40字程度の日本語で答えよ。 ただし, 句読点も字数に数える。 ウ 11 6 1 問5 次の文を第3パラグラフ (Ihave enough friends...) に入れるとき,本文中の①~ のうちのどの位置に入れるのが最も適当か、 次のア~エのうちから一つ選び, 記号 で答えよ。 9 3 Each step is complex, for if there are three ways of doing something, then there are sure to be strong proponents of each of the three ways, plus people who will argue that it is too early to standardize. 70 問8 最終パラグラフ (With all these difficulties...) の内容をもとに, 次の Question に2 語程度の英語一文で答えよ。 Question: According to the writer, why is the standardization of the everyday clo necessary? イ 2 ウ H O 問6 本文中の空所 (4) に入れるのに最も適当なものを、次のア~エのうちから一つ選び 記号で答えよ。 7 a single standard 1 several different standards ウ the same standard I too few standards <<-20-> <-21->

回答募集中 回答数: 0