#三角関数
March 18, 2024: Studying Maths (42), Trigonometry-3, 数学の勉強（42）、三角関数-3）
I have just finished the third round of trigonometry in maths. I enjoyed it as much as I did in the second round. The next round is the last part of this section.
三角関数の３回目を終えました。 2回目と同じくらい楽しめました。次回は
March 11, 2024:Studying Maths (41), Trigonometry-2, 数学の勉強（41）、三角関数-2）
I worked on trigonometry in maths. It was the second time. Surprisingly, it was good fun. The questions were less hard than I expected. I did not have to struggle with them. But I still have two more
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March 4, 2024: Studying Maths (40), Trigonometry, Imagination（数学の勉強（40）、三角関数、想像力）
I have studied the first part of trigonometry on my own. It was very difficult, as I expected. I hit the wall right from the start. I was unable to understand what was in the textbook well. I needed a
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三角比・三角関数の公式を単位円と関連づけて理解する
高校数学のなかで、いちばん多くの公式が登場するのが三角関数の単元かもしれません。確かに、式にすると数が多くなってしまいますが、実は単位円を用いることで公式として覚えるよりもずっと楽に、しかも公式を覚えるよりもずっと深く理解することができます。
cos θ の意味まず、次の図のような状態を考えましょう。
単位円があります。そこに、x 軸の正の向きから θ だけ傾いた、長さが 1 の棒がありま
June 25, 2023: Studying Maths (13), Graphs (2)（数学の勉強（１３）、グラフ（２））
I had been doing various types of graphs for the last ten days. Quadratic and reciprocal graphs were not so difficult to do. But the Sin and Cos graphs were so difficult that I could not answer the pr
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