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数学 高校生

この三角比の問題で、黄色のマーカー部分について質問です。なぜcos²>=0とわかるのでしょうか。教えてください🙇‍♂️

演習問題 (1)tan0 = 1 =113 (0°<8<90°) のとき, sin(90°-8) の値を求めよ。 (2) cos 'f = sin Q……… ① のとき, + 1+cose 1 1 cose の値を求めよ。 (甲南大) ヒント! (1)sin(90°-9)=cos日より,1+tan' = 1 = cos² の公式を利用すれば いい。(2)cos' = 1 - sin'@から、まずsing の値を求めればいいんだね。 頑張ろう! 解答&解説 ココがポイント (1) 公式:1 +tan' 1 √√15 =. ーに, tang= cos2 3 15 V15 を代入してtan' = 1/8=13 5-3 5 8 1+1=123=c030 cos2 = 338 I 1 13 √6 I ここで,0°<0 90°より, =18 = 10° <6<90° より cose > 0 よって,求める sin (90°-0)=cose は, √6 (i) 90°が関係しているの で, sin→ cos sin(90°-0)=cose = ..(答) (i)=30°とみて 4 sin (90°-30℃)>0 (2)cos'e=1-sin20 公式sin' + cos'0=1 ∴.符号は正 これを cos' = sine ・・・ ① に代入して, 1-sin20=sin sin20+sin0-1=0 これを解いて, sine = -1+V5 sin=t とおくと f+t-1=0 2 ・・・② (sine≧0) - 1±√12+4 t= だけど, 2 t=sincos'a≧0より 01 1 -1±√5 + t=sin0= -だね = 2 よって, 与式の値を求めると, 1+cose = 2 1-cos20 1 - cose (sino (①より)) 1-cos+1+coso (1+cost) (1-cost) 2 2 1 - sine 1. ・1+√5 2 4 = 3-V5 325 =3+√5 4(3+√5) | cos'e = sine ①, sin 0 = -1+√5 ....2+ (答) 分子分母に 3 +15

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英語 高校生

4~8の問題を教えて欲しいです。 お願いします。

Reading 2 Bear's Pie こは、アメリカのある小さな ストラン。 営む夫妻には, がいるのですが……。 3 {, R: Richard White (=Mr. White) S: Susan White (=Mrs. White) Mr. and Mrs. White have been running a small but popular restaurant for Bobby Richard (=Mr. White) Bear's Pie 2 take over を引き継ぐ argue singer. You should s アーキュー/ fiercely by is Mr. and Mrs. White's only child. He wanted to be a singer, but White wanted him to take over the restaurant as a cook. Mr. White membered the day when they argued fiercely. I want to be a singer. I love music! (angrily) No, you can't be a take over this restaurant. I really understand how you feel, Dad. I love the restaurant, too, but I have my own dream! professional musician is impossible. I Being a /fanliフィナスリ/ angrily angali アングリリ/ hate to say this, but your dream will end up 10 just as a dream. Mr. White was very stubborn. However, Bobby couldn't give up his dream, and finally he left home. obileb of soil I hate to say thi こういうことは ないが a long time, and tonight is the last day of their restaurant. R: It's time to close, Susan. S: No, not yet, Richard! It's too early. 5 R: Why? It's almost ten. S: Wait! Bobby said he'd show up tonight. I know he will. R: I don't think so. It's been ten years since he Hoe left home. 5: Yes, but tonight is special for all of us. : We haven't heard anything from him. I guess he has forgotten us. I don't believe that! He can't have forgotten. long has it been since Bobby left home? Question What was Bobby's dream?

解決済み 回答数: 1