f(x)=log_ax   ,  a>1

f(x)=log_ax   ,  0<a<1

x

y

α

rcosα

rsenα

(x,y)

r

f(x) = log(x)
g(x) = log(-x)
O = Intersect(xAxis, yAxis)
B = (1, 0)
c = Circle(O, B)
P = Point(c)
a = OrthogonalLine(P, xAxis)
A = Intersect(a, xAxis)
b = Segment(P, A)
d = OrthogonalLine(P, yAxis)
C = Intersect(d, yAxis)
e = Segment(P, C)
D = (0.68, 0.52)
h = Segment(O, P)
α = Angle(A, O, P)
i = Segment(O, A)