Question: can you color a certain part of a 2d plot, for instance a line up to x=0.5 if you have a hyperbel curve?

Dear community, 

I'm new to maple and was wondering if you could help me out.

I have this curve where I want to make a line that goes from x=0.5 up to its value on the curve in this case 1.60 and then all the way to the y-axis so there is an area under the curve which I can color if that's even possible?

I have the following in maple:

k := 2.5;
                              2.5
Ca0 := 1;
                               1
v := 20;
                               20
Ca := Ca0*(1-x);
                             1 - x
Fa0 := Ca0*v;
                               20
Cb := Ca0*x;
                               x
ra := k*Ca*Cb;
                         2.5 (1 - x) x
plot(1/ra, x = 0 .. 1);
 

thank you for your help

Best Regards

Saad