#社山

[kiichilog]

2024.11.4 社山 日光中禅寺湖の紅葉、社山に登頂 向こうは男体山、太郎山、山王帽子山、中禅寺湖

Mt.Shazan (1826m)

[inefekt69]

Nunakuma Shrine - Tomonoura, Japan

[brownie-pics]

'24.6.11 手向山八幡宮、水谷茶屋、春日大社、浅茅ヶ原にて

前回投稿の続編、枚数多めｗ

手向さんから春日大社を経由して再度浅茅ヶ原へ。カラスさんや小鳥さん、茶屋の茅葺や春日さんの柱まで、やはりこの日はごきげん麗しく感じられました。もちろん子鹿ちゃんもニコニコと元気。

こんな日は写活後のお昼ご飯も美味しいｗ

[wankohouse]

博多祇園山笠

博多祇園山笠

[masachi]

ちょうど良い感じの光がさしていて。

[crazyfox-archives]

The large torii gate to Kumano Hongū Taisha Grand Shrine (熊野本宮大社) in Tanabe, Wakayama Prefecture, surrounded by rice fields in early May

La gran puerta torii del gran santuario de Kumano Hongū Taisha (熊野本宮大社) en Tanabe, prefectura de Wakayama, rodeada de campos de arroz a principios de mayo

Image from the shrine's official twitter account on May 4, 2024

[merpmonde]

Sangaku Sunday #6

We are about to solve our first sangaku problem, as seen on the tablet shown above from Miminashi-yamaguchi-jinja in Kashihara.

First, we should conclude our discussion: what are sangaku for? There's the religious function, as an offering, and this offering was put on display for all to see, though not all fully understood the problems and their solutions. But a few people would understand, and these would have been the mathematicians of the time. When they visited a new town, they would typically stop at a temple or shrine for some prayers, and they would see the sangaku, a sample of what the local mathematicians were capable of. Whether the problems were solved or open, the visitor could take up the challenges and find the authors to discuss.

And this is where everything lined up: the local school of mathematics would have someone new to talk to, possibly to impress or be impressed by, and maybe even recruit. With the Japanese-style mathematics of the time, called wasan, being considered something of an art form, there would be masters and apprentices, and the sangaku was therefore a means to perpetuate the art.

Now, what about that configuration of circles, second from right on the tablet?

Recall that we had a formula for the radii of three circles which are pairwise tangent and all tangent to the same line. Calling the radii p, q, r, s and t for the circles of centres A, B, C, D and E respectively, we have

for the circles with centres A, B and C (our previous problem), and adapting this formula to two other systems of three circles, we get

for the circles with centres A, C and D, and

for the circles with centres B, C and E. Add these together, and use the first relation on the right-hand side, we get a rather elegant relation between all five radii:

Of course, we can get formulas for s and t,

r having been calculated previously using just p and q, which were our starting radii.

For example, setting p=4 and q=3, we get, approximately, r=0.86, s=0.4 and t=0.37 (this is the configuration shown in the figure, not necessarily the one on the tablet - I will be able to make remarks about that on another example).

[kankan70]

可愛い無人駅②

[nagaino]

[aka-nyontaros]

[lets-take-a-break]

本山山神社（吹矢ふるさと村）　Yama shrine (Fukiya Furusato Village)

岡山県高梁市　Takahashi-shi, Okayama, Japan

2024/03

[yoooko-o]

16/11/2024

今日のちょいカフェの日替わりlunchは幕の内でした🍱

左はレモンケーキ🍋 レモンは沖永良部産のレモンを使ったオーナーこだわりのケーキ

右はさつまいもチーズケーキ🍠 さつまいももオーナーが自宅で育てた紅はるかです🤗

今日は久しぶりに姶良市の蒲生八幡神社へ⛩️

大山祇神社⛩️

ここはちょいカフェオーナーのおススメの隠れた黄葉スポットだそうです🤗

そして、久しぶりの藺牟田池🦢

紅葉がちらほら始まっていました😄

薩摩川内市入来町

ここもちらほら紅葉🍁

散々遊びまわって、最後は徳丸屋さん🍰

日没後の訪問だったのでお店の人もびっくり👀イートインも快くしてもらいました🥰

私は久しぶりのWチーズケーキ🧀

明日は運動必須です笑

[kyotodreamtrips]

This is the thirteen-story wooden pagoda of Tanzan jinja in Sakurai-shi, Nara-prefecture. It was built in 1532 and is a reconstruction of the structure built by Jo'e in the Asuka Period.

[brownie-pics]

Look at a point 👀

’24.7.21 飛火野、手向山八幡宮、東大寺、春日大社にて

[wankohouse]

英賀神社　春日神社　山崎

山崎村　英賀神社（本宮）・春日神社（宵宮）

＊山崎村春日神社が地元

[shodoshima-camera]

小豆島の各地で、秋の太鼓まつりが開催されています。

たくさんの人たちの手で太鼓台があげられる姿に毎年感動します。 手手手手手！

力をあわせるってこういうことなんですよね。 えいしゃしゃげ！

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