ベクトル値函数の微分：双曲線
Author: knxm

t = 1.1 (slider from -5 to 5, step 0.1)
f(x) = (exp(x) + exp(-(x))) / 2.0
g(x) = (exp(x) - exp(-(x))) / 2.0
A: (f(t), g(t))
O = Intersect(xAxis, yAxis)
u = Vector(O, A)
h = 0.01 (slider from 0.01 to 2, step 0.01)
B: (f(t + h), g(t + h))
v = Vector(O, B)
w = Vector(A, B)
C: A + w / h
z = Vector(A, C)