Could you help me reformulate this equation to depend on a single variable?

The two variables and are defined as following:

Also, the variables are defined as shown in the following image:

But, the equation is obtained if we fix one of the points, or , at the center between and as follows:

This means that, always, so will only depend on the distance between the points and , wich is . and will always vary if varies, so they can be defined as dependant of a single variable () but I can find out how to do it.

I only know that the function should look like this if it is plotted along distance .

(This picture and the past ones should tell the same information, they are the same.)

Thank you for your attention.

15.2() = 1 + ( (1-) (1-2) ? 5(+ cos))) c la . P2b r16 +. T P1 rla Fa rib AF b r2a r2b Fb P2 191,2(7) P F Fo Fa ria Pi r2a rib b r2b F P2 Tla = T 16 72b P2 Source * Pi (Fixed) 15.2() = 1 + ( (1-) (1-2) ? 5(+ cos))) c la . P2b r16 +. T P1 rla Fa rib AF b r2a r2b Fb P2 191,2(7) P F Fo Fa ria Pi r2a rib b r2b F P2 Tla = T 16 72b P2 Source * Pi (Fixed)