Σ an = ∞ an = 1/n+(n−m)d T.theodor 2022.11.6.

y = a'xn+b'xn-1…+x+z' △ABC = 1/2√(x2−x1)2+(y2−y1)2(y1−y2−y1/x2−x1x1−y3+y2−y1/x2−x1x3) T.theodor 2022.11.6.

lim ∮f(y)/∮f(x) = (x →∞) T.theodor 2022.11.6.

nπ+a = (n+a/π)π T.theodor 2022.11.6.

rhombus a 之 diagonal 0 a:b = cosθ:sinθ b>2a a:b = cosθ:sinθ T.theodor 2022.11.6.

△ABC 1/2∠BAC+1/2∠BAO = 90° T.theodor 2022.11.6.

△ABC 之 1/2∠ABC, 1/2∠BCA 之 交点O ニ於ル相似ニヨリ 90°. T.theodor 2022.11.6.