x2y2 2F3 x + y2k + 1 x + y2k + 1 ab/2 a0 + 1a1 + 1a2 + 1a3 + 1a4 a0 + 1a1 + 1a2 + 1a3 + 1a4   n k/2     p 2   x2pp − 2 − 11 − x 11 − x2 ∑0 ≤ i ≤ m0 < j < n P(i , j) x2y p∑i = 1 q∑j = 1 r∑k = 1 aijbjkcki (1 + (1 + (1 + (1 + (1 + (1 + (1 + x)1/2)1/2)1/2)1/2)1/2)1/2)1/2 [ ∂2∂x2 + ∂2∂y2 ] |φ(x + iy)|2 = 0 222x t∫1 dtt ∬D dxdy f(x) = 1/3if 0 ≤ x ≤ 1 2/3if 3 ≤ x ≤ 4 0elsewhere k times x + ⋯ + x yx2 ∑p prime f(p) = ∫t > 1 f(t)dπ(t) { k a's a, … , a , l b's b, … , b  k + l elements}     a b c d     e f g h   0   i j k l     det c0 c1 c2 ⋯ cn c1 c2 c3 ⋯ cn + 1 c2 c3 c4 ⋯ cn + 2 ⋮ ⋮ ⋮ ∷ ⋮ cn cn + 1 cn + 2 ⋯ c2n > 0 yx2 x3141592 + π xzdcyab y‴3