餘弦定理
Author: 藍邦偉　老師

餘弦定理

a²=b²+c²-2bccosA

b²=a²+c²-2accosB

c²=a²+b²-2abcosC

A = (8.651949910554562, 4.162754919499106)
B = (4, 0)
C = (10, 0)
多邊形1, c, a, b = Polygon(A, B, C)
d = Circle(A, B, C)
n = 3 (slider from 0 to 4, step 1)
α = Angle(B, A, C)
β = Angle(C, B, A)
γ = Angle(A, C, B)
r = Radius(d)
e = LineBisector(B, C)
f = LineBisector(A, C)
文字1: "c= \overline{ AB }=" + a + ",a= \overline{ BC }=" + b + ",b= \overline{ CA }=" + c
文字2: a^(2.0) + "=" + (b^(2.0)) + "+" + (c^(2.0)) + "-2\times{}" + b + " \times{  } " + c + "\times{}" + (cos(α))
文字4: b^(2.0) + "=" + (a^(2.0)) + "+" + (c^(2.0)) + "-2 \times{  }" + a + "\times{} " + c + "\times{}" + (cos(β))
文字5: c^(2.0) + "=" + (a^(2.0)) + "+" + (b^(2.0)) + "-2" + "\times{}" + b + "\times{}" + c + "\times{}" + (cos(γ))