黄色で囲ってあるところの式変形がよく分からないんですが、どう計算したらこうなりますか？

256 ➤ X X 基本例 158 和と積の公式 (1)積→和,和→積の公式を用いて、次の値を求めよ。 (ア) sin 75°cos 15° (イ) sin 75°+sin 15° (2)△ABCにおいて、次の等式が成り立つことを証明せよ。 (ウ) cos 20° cos 40° cos80 A sin A+ sin B+ sin C=4cos COS COS cos C 2 p.255 基本事項 1,2167 B 2 2 解答 指針 (2) △ABCの問題には, A+B+C=π (内角の和は180°) の条件がかくれている A+B+C=xから、最初にCを消去して考える。 そして、 左辺の sin A+ sin B に 和積の公式を適用。 (1)(ア) sin 75° cos15°=1/12 {sin(75°+15°)+sin(75°-15°)} 3 2+√3 1/(1+1/2-2/ 4 = (sin 90°+sin60°)=2/12(1+ (イ) sin 75°+sin15°=2sin 75°+15° 2 COS 75°-15° 2 =2sin45°cos 30°=2. 23 2 6 2 2 (ウ) cos 20° cos 40°cos 80°= 1 {cos 60°+cos(-20°)}cos 80° 2 = -/1/11/ 1 1 +cos 20° cos 80° cos 80°+ ・cos 20° cos 80° 2 22 = -1/cos80+1/2 1/2(cos 100°+cos (160)-1/2Cos80°+1/cos100+1/2 = 4 22 4 4 4 ・cos =1/cos80°+1/cos(180°-80°)+1/13-1/2COS80°-1/2COS80°+21/18-1 == (2) A+B+C=πから C=πー(A+B) ゆえに よって 4 8 sinC=sin(A+B), cos =cos(A+B)=sin A+B 8 2 A+B A-B A+B 2個の sinA+sinB+sinC=2sin COS +sin2. 2 A+B A-B 2 公 A+B\ =2sin COS +cos 2 2 2 和双 2 =4 2 ・COS COS 2 =2 cos 2 cos cos(-) A B -4coscoscos A 2 K の公 C 2 練習 (1) 積和, 和→積の公式を用いて, 次の値を求めよ。 ③ 158 (ア) cos 45°sin 75° (イ) cos 105°-cos 15 (ウ) sin 20° sin 40° sin 80° (2)△ABCにおいて,次の等式が成り立つことを証明せよ。 cos A+cos B-cosC=4cos- A B C scossin-1 *cos sin 2 2 2 p.270 EX 100

計算の手順は理解できるんですが、それぞれの計算が何を求めるための計算なのかがイマイチ理解できてないです。分かりやすく教えていただけると幸いです🙇‍♀️

00000 246 基本 例題 153点の回転 点P(3, 1), 点A(1, 4) を中心としてだけ回転させた点をQとする。 解答 π (1)点Aが原点Oに移るような平行移動により、点Pが点P'に移るとする。 点Pを原点を中心としてだけ回転させた点 Q'の座標を求めよ。 (2)点Q の座標を求めよ。 p.241 基本事項 指針 点P(x, y) を、原点を中心として0だけ回転させた点を Q(x, y) とする。 ye Q(rcos(a+9), rsin(a+0)) r P 0 (rcosa, a rsina) O x OP=rとし,動径 OP と x軸の正の向きとのなす角をと x=rcosa, y=rsina すると OQ=rで,動径OQとx軸の正の向きとのなす角を考える と、加法定理により x=rcos(α+0)=rcosacoso-rsinasino =xcoso-yosino y=rsin(α+0)=rsinacos0+rcosasino =yocos0+xsino この問題では,回転の中心が原点ではないから,上のことを直接使うわけにはいかな 3点P, A, Q を,回転の中心である点が原点に移るように平行移動して考える。 方向に -4 だけ平行移 (1) 点 A が原点 0 に移るような平行移動により,点Pは点 x軸方向に -1, y軸 P'(2,-3) に移る。 次に点Q' の座標を (x', y') とする。 また,OP'=rとし, 動径 OP' とx軸の正の向きとのなす 角をα とすると 2=rcosα, -3=rsina 動する。 π π よって x=rcos(a+/-rcosacos - rsinasin 3 3 rを計算する必要はな -2-(-3).√32+3√3 y=rsin(a+1)-rsinacos/ trcosasin A 1 =-3.+2.√32√3-3 2 したがって、点Q'の座標は (2+3/3 2/8-3) い。 y 3 4 1 PQ' 0 12/3 (2) 点Qに移るから,点Qの座標は Aに移るような平行移動によって, Q'は,原点が点 3√3+1, 2√3-3+1) 45 (4+3√3 +1)から(4+3.3 P 2√3+5) (1)点P(-2,3)を,原点を中心としてだけ回転させた点Qの座標を求め 練習 ③ 153 (2)P(3,-1), 点A(-1, 2) を中心として TC だけ回転させた点 Q 標を求めよ。 3 p.254 EX95

この問題はどのように解くのがコツなのでしょうか？ (6)のみあっていて(5)の答えであるDは、4か5で悩んでいたので納得できているのですが他の問題がわかりません。もともとこのような問題形式が苦手なので教えて頂きたいです。お願いします。

3 Choose the most appropriate words to complete the sentences. 1) We can't find Ann anywhere. She ( ). 2) The children made a lot of noise in the train. Their parents ( ) them. 3) You ( ) him on the street. He is still in the hospital. 4) You had enough time then. You ( ) at such a speed. 5) She doesn't have money with her now. She ( ) all her money on clothes. 6) The garden is all wet. It ( a) cannot have seen d) should not have spent ) last night. b) must have rained e) need not have driven c) may have gone home f) should have scolded

28番ですがマーカーを引いている部分がわかりません。 電気量が中和されるが電気量が不変ということですか？ そうだとしたら矛盾しているように感じます。

d 2d 3d D S EX 4枚の同じ極板を図のような間隔で並べ, 起 電力Vの電池につないだ。 はじめスイッチ K A B K と (II) 下 ると (図2 とに ABCD + E ← E → ↑ だ。 は閉じられ, Sは開かれている。 接地点の電位 を0として, 極板Bの電位を求めよ。 次に,S を閉じたときのBの電位を求めよ。 解 極板間隔d, 2d 3dの3つのコンデンサーの直列 と見ると、 電気量が等しいから,電場Eも等しい。 VBD= .. 5 y V AD 間について V=Ed+E・2d+E•3d=6Ed BD 間の電位差を VBD とおくと VBD=E・2d+E・3d =5Ed 6 Dの電位は 0 であり, Bの方が高電位だから、この値 はそのままでBの電位になっている Sを閉じると, BとCが等電位になり, BC 間はコ ンデンサーではなくなる (電位差 0 だから電気量 0)。 AB間, CD 間の2つの直列になり、電場をE' とする と AD 間について V=E'd+E' 3d =4E'd AB E' CD 間について Vcp=E'・3d . VCD=3V この値はCの電位でもあり, Bの電位でもある。 -V [BD] [ -VCD- いの 電仁 電て E らこ

英語の共通テスト対策の問題です。 答えがあっているか、間違っていたら答えを教えてください🙇‍♀️

第2問対策 意見文の読み取り ③ No. Name Class Tomom 目標解答時間: 7分 共通テストドリル リーディング 改訂第5版 Your English teacher gave you an article to help you prepare for the debate in the next class. A part of this article with one of the comments is shown below. Net Shopping: Convenient but Addictive By Tony Sutton, Philadelphia 12 June 2019 9:20PM Internet shopping is very convenient. At night or when it is raining or snowing. 1.66 billion people (in the world) are estimated to have used the Internet for shopping in 2017.) In the same year, you can buy things comfortably from your room. total sales of online retail amounted to 2.3 trillion US dollars. It is predicted that the amount will reach 4.48 trillion US dollars(in 2021.) Some people object to this situation which could be described as a retail revolution. A male says, "I was one of those who became addicted to the convenience of online shopping and was purchasing almost everything online. But now, when I need something, I first think of going to a store to look for it." A female says, "The goods which are delivered are sometimes different from what I had in my mind. As it is troublesome to send them back, I end up using something that I do not really like. If I buy things at stores, such a situation does not happen so often. I will not buy unnecessary things, so I will not regret shopping. Therefore, recently I seldom shop online, and instead buy things at stores after seeing them directly." 9 Comments Newest Jennifer Frazer 20 June 2019 9:32AM /10 I also bought too many things online before, but now I have come to order only necessary things. The point is how to control yourself. As there are few shops in my neighborhood and there are plenty of goods on the Internet, I will continue to use the Internet for shopping. (★およそ280 words) 問1 According to the article, the total sales of online retail will 1 at 0 0 be four times as large as in 2017 ② be less than 1.66 billion US dollars decrease by about half in four years ④ increase to nearly twice as much in four years 問2 ①②③④ (2点) Your team will support the debate topic. "It is better to buy things at stores than to buy through the Internet. In the article, one opinion (not a fact) helpful for your team is that people 2 can buy only necessary things online 2 might be given a discount at a store 3 might buy unnecessary things at a store tend to buy unnecessary things when shopping online 1 2 3 4 (2点) esc 3 The other team will oppose the debate topic. In the article, one opinion (not a fact) helpful for that team is that 3 0 it is possible for you to shop comfortably online it takes some time for the goods ordered online to arrive 3 people can return the delivered goods if they do not like them people have to pay transportation fees to and from stores ① ② ③ ④ (2点) 7-2 © Z会 2025 [不許複製禁転載]

英語の共通テスト対策の問題です。 答えがあっているか、間違っていたら答えを教えてください🙇‍♀️

You are the editor of a school English paper. Stephanie, an exchange student from the US, has written an article for the paper. More Moon Decor Loun Where do you live? When people think of the places with the "best quality of life," they often imagine NY, London or Hong Kong, with exciting nightlife, parks, and tourist sites. However, many studies have concluded that (big cities do not offer the highest quality of life. Let's take a look at the results of the studies. In a recent survey of 56 cities on quality of life, only one big city, Tokyo, was in the top half of the ranking. Edinburgh (UK) came in fourth. It is almost even with Copenhagen (Denmark), but is far behind Zurich (Switzerland) Zurich beat Wellington (New Zealand), which came in second. These four winners are all mid-sized cities. Research shows that people were increasingly moving to mid-sized cities because: ▸▸ Housing costs can be up to 50% cheaper Property taxes can be up to 25% lower Fuel costs can be up to 4% cheaper Cultural attractions in these cities are also comparable to those of big cities. Mid-sized cities have culture that is just as attractive as that of large cities. Of course, people say mid-sized cities have some problems, for example, public transportation is usually less developed and jobs are somewhat fewer than big cities. 問1 /10 ング 改訂第5版 In terms of quality of life, which shows the cities' ranking from highest to lowest? 1 0 Copenhagen - Edinburgh - Wellington-Zurich [② ③ Copenhagen-Wellington-Zurich - Edinburgh Zurich Copenhagen - Edinburgh - Wellington Zurich-Wellington - Copenhagen - Edinburgh RUOTA P ①②③④ (2点) 2 According to Stephanie's report, one advantage of a mid-sized city is ①cultural activities are equal to those in big cities 2 guides are friendlier than in small towns property taxes are about the same as other locations public transportation is cleaner than in big cities ① ② ③ ④ (2点) how 問3 The statement that reflects one finding from the research is 3 ①Both rural areas and big cities have plenty of excitement.' 3 Keep your options open when choosing a place to live in.' People are moving to big cities nowadays to earn more.' 4 The best cities to live in may not be the biggest. ① ② ③ ④ (2点) Which best summarizes Stephanie's opinions about the towns and cities of Japan? 問4 4 I believe this same trend might be true (in Japan) as well. In some local guidebooks, Nagoya and Sendai - two mid-sized cities were among the top five places (in Japan) for quality of life. Housing and other living costs (in both these cities) are also cheaper than those of big cities. ①A more international lifestyle is available in Tokyo of Osaka. Big and mid-sized cities are similar in most ways in terms of job opportunities. 3 City governments try to provide easy access to public transportation. Mid-sized cities are getting more popular than big cities. (★およそ270 words) ① ② ③ ④ (2点)

英語の質問です 答えは線で引いたところです 解説をして欲しいです

[11] 次の英文のae の英文の( )にはどの語が入りますか。もっとも適当なものを ①〜③の 中から1つずつ選びなさい。 a. Remember ( turned to turn turning) off your computer before leaving today. b. Haruki Murakami is a writer ( knew known knowing) all over the world. c. Let me introduce (① me mine myself). I'm Ken from Japan. least) expensive bicycle among d. Which is the ( little less these? e. Jack used to (① go gone 3 going) fishing when he was a child. 12 次の英文のaeの英文の意味が通るようにするには、( )の中の語句をどのように並べ たらよいですか。正しい順序のものを ①~④の中から1つずつ選びなさい。 a. His parents (1. always 2. read 3. him 4. make) good books. [ 1-2-4-3 21-4-3-2 2-4-3-1 ④3-2-4-1] b. It's important to study (1. not 2. languages 3. but 4. only) cultures. [ 1-2-3-4 ② 142.3 3 3-1-4-2 ④ 4-1-3-2] c. Let's keep (1. each 2. with 3. touch 4. in) other. ② 2-3-14 33-4-1-2 ④ 43-2-1] [ 2-1-4-3 d. Go to bed (1. as 2. to 3. so 4. early) stay healthy. [ 1-2-3-4 ② 23-4-1 ③ 3-14-2 4-3-1-2] e. All you (1. is 2. have to 3. do 4. study) if you want to pass the next exam. [O 2-3-1-4 ② 2-4-1-3 ③ 3-1-2-4 @ 4-1-2-3] <-14-> [和6年度 第73回2級]

⑵の問題で、矢印のところの式変形がどういう考え方でそうなるのかわからないです。詳しく教えていただきたいです。

256 基本 例題 158 和と積の公式 ()sin 75° cos 15° X (1)積→和,和→ 積の公式を用いて, 次の値を求めよ。 (1) sin 75°+sin 15° (cos 20° cos 40° cos 80° X (2)△ABCにおいて、次の等式が成り立つことを証明せよ。 指針 B 2 C sin A+sin B+sin C=4 cos A COS COS 2 p.255 基本事項 1.2 重要 167. (2)△ABCの問題には,A+B+C=π (内角の和は180°)の条件がかくれている。 A+B+C=x から 最初にCを消去して考える。 そして, 左辺の sin A+ sin B に 和積の公式を適用。 18 2 (1) sin 75°+sin 15°=2sin- (1) sin 75° cos 15°= {sin (75°+15°)+sin(75°-15°)} 解答 (sin 90° + sin 60°)=( 75°+15° 75°-15° 2/(1+ √3)=2+ √3 4 COS 2 2 √6 =2 sin 45°cos 30°=2. 2 2 2 () cos 20° cos 40° cos 80°= {cos 60°+cos(-20°)}cos 80° 2 = 97 = 121414 -/1/1/ +cos 20° cos 80°= 2 14 cos 80°+ cos 20° cos 80° 2 cos 80°+ 11 22 1 {cos 100°+cos(-60°)}= = cos 80°+ cos 100°+ 1 1 1 1 cos 80°+ cos(180°-80°)+ cos 80°-cos 80°+ 4 4 8 4 4 8 8 (2) A+B+C=πから С=π-(A+B) 20 ゆえに sinC=sin(A+B), cos=cos(A+B). A+B = sin 1980 A+B A-B よって sin A+sin B+sin C=2sin- A+B COS + sin 2. 2 2 2 991 =2sin (A+B A-B A+B\ COS 2 +cos 2 C よう =2 cos/1/cos/cos(-1/2) A B 8-8-4 coscos cos B COS 2 練習 (1) 積和, 和→積の公式を用いて,次の値を求めよ。 (1) cos 105°-cos 15° ③ 158 (7) cos 45° sin 75° ()sin 20° sin 40° sin 80° (2)△ABCにおいて,次の等式が成り立つことを証明せよ。 cos A+ cos B-cos C=4 cos A B Coscos sin 2-1 COS 2 p.270 EX 100

英語の共通テスト対策の問題です。 答えがあっているか、間違っていたら答えを教えてください🙇‍♀️

tood wonal algo al dal 目標解答時間: 7分 問1 You are an editor at a school English blog. Andrea, an exchange student from the US, has written an article for the blog. Studies show that children's physical and mental health, as well as their academic performance, improves through healthy school lunches. Experts say that school to learn lunches are a chance for children to enjoy a wide variety of dishes, and about the food history and culture of their nation and the world. In that sense, the lunchroom is also a classroom. Yet, both American and Chinese students waste large amounts of lunch food. Why is that? The following survey results may hint at one possible answer. estra ▸▸Less than half of American schoolchildren rate their meals as tasty enough to eat. This is higher than in Beijing in China, where children are less satisfied with their meals. ▸▸A large majority of schoolchildren in France, followed very closely by South Korea say they are satisfied with their school lunch, and lunch waste in both these countries is not much. Students in both countries look forward to their school meals. The United States Department of Agriculture (USDA) manages public school lunches (in America. The USDA requires school lunches to include plenty of vegetables and fruits, whole grains, milk and at least one meat item or another food item as nutritious as meat. The USDA lunch program in 2020 cost about US$10 billion. provided Despite USDA's efforts, it seems American children are not happy with the school meals they get since the lunch waste level is so high. However, we shouldn't waste food. On the other hand, since coming to Japan, I've learned Japanese students try not to waste food because they have been taught its value. The lunchroom works well as a classroom. 共通テストトリル /10 リーディング 改訂第5版 In terms of lunch satisfaction, which shows the countries' ranking from highest to lowest? China-France-the US - South Korea China the US-France - South Korea South Korea - the US-China the US-China - South Korea (2) ③ France ④ France 6 South Korea - France - China - the US 6 South Korea - France - the US-China ① ①②③④⑤⑥ (2点) 2 According to Andrea's blog post, one advantage of a healthy school lunch is that 2 children will learn to cook meals 2 food preparation costs will decrease learning history will become easier ④overall student academic scores may rise ① ② ③ ④ (2点) 3 The statement that best reflects one finding from the surveys is 3 問4 ① 'Children enjoy school lunches if they taste good.' ② 'Countries with big budgets can provide truly good meals." ③ 'Schools should focus on nutrition to avoid food being thrown out." 'Teachers must punish children who do not eat their school meals." 1 2 3 4 (2) Which best summarizes Andrea's opinions about Japanese schools? They explain importance of not wasting food, which works well. 2 They have enough time to enjoy school lunch. They have wonderful lunchrooms. They show students how to cook national dishes. 4 ① ② ③ ④ (★およそ290 words)

この問題の(3)なのですが、Aを求めることになると、点Aと直角が位置している点を繋げた線を底辺として考えるのが正解ですか？ また、2枚目の公式が(3)にはアルファベットが当てはまったないように感じたのですがそうですか？ よろしくお願いします。

305 次の△ABCにおいて, sin A, cos Atan A の値を求めよ。 (1) B (2) b C (3) C A C a A B 2570 b