Coloring between an ellipse and a line

[Dustinsfl]

I drew an ellipse and then bisected it with a line with the basic \draw.
How can I color/shade from the line to the ellipse boarder? We can't use

\filldraw () -- () arc ( : : radius)

since the radius of an ellipse changes.

 

[NateD]

Here is my code (which doesn't compile):<code>\documentclass[12pt]{article}\usepackage{tikz}\begin{document}\begin{tikzpicture}[scale=1] \draw (0,0) ellipse [x radius = 3cm, y radius = 2cm]; \draw (0,0) -- (0,4); \filldraw[bottom color = blue!50, top color = red!50] (0,2) arc (0:180 : {(3+2)/2});\end{tikzpicture}\end{document}</code>A:Just draw the arc.<code>\documentclass[12pt]{article}\usepackage{tikz}\begin{document}\begin{tikzpicture}[scale=1] \draw (0,0) ellipse [x radius = 3cm, y radius = 2cm]; \draw (0,0) -- (0,4); \draw[bottom color = blue!50, top color = red!50] (0,2) arc (0:180 : {(3+2)/2});\end{tikzpicture}\end{document}</code>