今天记一些杂事。
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Tower of circles
Consider N circles stacked on top of each other inside an isosceles triangle, as shown in below for the case of N=4. Let \(A_C\) be the sum of the areas og the N circles, and let \(A_T\) be the area of the triangle. In terms of N, what should the...
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Angles
Quadrilateral ABCD has angles
\(\angle{BAC}=80^{\circ}\)
,
\(\angle{CAD}=20^{\circ}\)
,
\(\angle{BDA}=50^{\circ}\)
, and
\(\angle{CDB}=50^{\circ}\)
. Find angles
\(\angle{BCA}, \angle{CBD}\)
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The Life of My Aspirations
理想中的生活场景，有意无意我想过很多次，
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The Three Types of Twilight
There is something transformational about twilight.
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