Solve x in Unsolvable Equation: d/(1-COS(L/(2*x)))

[creeve4]

Solve for x:

x=d/(1-COS(L/(2*x)))

where L=28 and d=0.2


I have been able to get x~490 by "guessing" values for x and computing, then repeating until both sides are equal.

There must be a better way, although neither my TI-89 nor Mathematica are able to do it.

 

[Mark44]

It's unsolvable by algebraic methods. The best you can do is to use numerical techniques to get approximate values.

 

[Dr.D]

When I solve this numerically with Maple I get x = 1.0618829.