領域

円領域を描きましょう。

領域の入れ替え

正解

赤い点を動かしましょう．

a = Element({1, 2, 4, 5, 8, 9, 10, 13, 16}, Random[1, 9])
ay = Random(-1, 1)
ax = Random(-1, 1)
e(x, y) = x^(2) + y^(2)  <  5
A = PointIn(e)
f(x, y) = (x - x(A))^(2) + (y - y(A))^(2) > 0.1
s = -1
B = PointIn(f)
f0 = Expand((x - ax)^(2) + (y - ay)^(2) - a)
n: (Random[0, 1] * 2) - 1
text3 = If(n ≟ 1, "\le ", "\ge ")
d(x, y) = (s * ((x(A) - x)^(2) + (y(A) - y)^(2) - (x(A) - x(B))^(2) - (y(A) - y(B))^(2))) ≥ 0
ans1: x(A) ≟ ax ∧ y(A) ≟ ay
ans2: ((x(B) - x(A)) * (x(B) - x(A))) + ((y(B) - y(A)) * (y(B) - y(A))) ≟ a
ans3: n ≟ (-s)
f1(x, y) = f0(x, y)
text1: "" + (LaTeX[f1]) + "" + (LaTeX[text3]) + "0を表すように"