(x,f(x))

(x+h,f(x+h))

f(x) = x - cos(x)
A_1 = Point(f)
B = Point(f)
a_1 = Line(A_1, B)
a = Point(xAxis)
b = OrthogonalLine(a, xAxis)
c = (6, 0)
c_1 = OrthogonalLine(c, xAxis)