Frequency of a Tuning Fork Formula

Equation for calculate frequency of a tuning fork is,

$$f=\frac{{1.875}^2}{2\pi l^2}x\sqrt{\frac{EI}{\rho A}}$$

where,
f = frequency the fork vibrates
1.875 = smallest positive solution of cos(x)cosh(x) = −1
l = length of the prongs
E = Young's modulus of the material the fork is made from
I = second moment of area of the cross-section to the fourth power
ρ = density of the material the fork is made from
A = cross-sectional area of the prongs (tines)