for many years i've had an equation to determine the diameter of a sphere to resonate a given frequency.

actually i've had two. one for a sphere with a sound hole and one for a sphere with a hollow neck/tube attached

as the sound hole. both types are used on traditional african xylophones. i would like to check the accuracy of both,

however this post concerns the equation for a sphere with just a sound hole.

i see in wikipedia that the equation, solved for the frequency is -

my equation is solved for the diameter and it is -

is my equation correct according to wikipedia?

thank you,

drew