多項式(13)
Author: 藍邦偉　老師

$ \overline{AB} =\sqrt{15²+20²}=25$

$ \frac{1}{2} ×15×20=\frac{1}{2}×25×\overline{OC}$

$⇒ \overline{OC}=12 ⇒C(0,12)$

$∵ \frac{\overline{AC}}{\overline{BC}}=\frac{\overline{OA}}{\overline{OC}}=\frac{\overline{OC}}{\overline{OB}} =\frac{4}{3}$

⇒\overline{OA}=16,\overline{OB}=9

⇒A(-16,0),B(9,0)

設f(x)=a(x+16)(x-9)

f(0)=12=a×16×(-9)⇒a=-\frac{1}{12}

$ ∴f(x)=-\frac{1}{12}(x+16)(x-9) =-\frac{1}{12}x²-\frac{7}{12}x+12$

f(x) = -(1 / 12) * x^(2) - 7 / 12 * x + 12
A, B = Intersect(f, xAxis)
C = Intersect(f, yAxis, 1)
a = Segment(A, C)
b = Segment(C, B)
u = Vector(A - (7, 0), B + (7, 0))
v = Vector((0, -10), (0, 20))
O = (0, 0)
n = 0 (slider from 0 to 10, step 1)
D = (-41.979881235668735, 20.633015912727934)
D_1: D + (12.5, 0)
D_3: D + (0, 6.5)
D_2: D_1 + D_3 - D
poly1, d, d_1, d_2, d_3 = Polygon(D, D_1, D_2, D_3)