Dunkerley's formula is given by

a. \(\omega_{1}^{2} \approx a_{11} m_{1}+a_{22} m_{2}+\cdots+a_{n n} m_{n}\)

b. \(\frac{1}{\omega_{1}^{2}} \approx a_{11} m_{1}+a_{22} m_{2}+\cdots+a_{n n} m_{n}\)

c. \(\frac{1}{\omega_{1}^{2}} \approx k_{11} m_{1}+k_{22} m_{2}+\cdots+k_{n n} m_{n}\)