Catenoid soap bubbles

[Albert Chan]

I don't understand the complexity.

Let R = D/2 = 1.068/2 = 0.534 m
Let H = L/2 = 0.5/2 = 0.25 m

First, with symmetry, b = 0.25 m (not need to solve at all)
Shift axis so that x=0 has radius of r (= Matt's a), x=H have radius of R

(y/r) = cosh(x/r)

At x=0, we have y = r
At x=H, we have y = R, (R/r) = cosh(H/r)

Casio FX-115MS, solve for r:

0.534 - X*cosh(0.25/X) [SOLVE] (guess r = R = 0.534)       → r = 0.465190824