Bug(s) in Ga Tech (and now, merged) mde code

[TerryHodgson]

Tested current MDE java app (DescriberAndGraphPanel.java) against MathTrax. Ran them both against all sample equations in doc/Miscellaneous/InputExamples. This showed several (legacy, Ga Tech version) bugs in the current version:

It doesn't recognize the following equations:
(x-h)^2/a^2 - (y-k)^2/b^2 = c-a
(x - ay)^2 - y^2 = 0
x^2 - y^2 = 0

The results are incorrect for the following set:
r = a/(1-b_cos(theta-d_PI/180)). The original example had e in place of b, signifying eccentricity of the ellipse, not exp.
x^2 - y^2 = c, where c is not 0. Should be a hyperbola, not two intersecting lines.
y = 10 -x^2/10 The description is correct, but the graph is either empty or outside the visible window.
y = a * x * cos(x - b) It is described as an unmodified cosine function, which it is not.
y = sin(x - a) - b * x + c It is described as an unmodified sin function, which it is not.

[TerryHodgson]

Need new tests for:
arcsine, arccosine, arctangent, secant, cosecant, cotangent, arcsecant, arccosecant, arccotangent

[TerryHodgson]

Which bug fixes, if any, are a priority?