Finding the Rayleigh damping coefficients mu and beta having the damping ratio

Hi All

How can I find all possible combinations of mu and beta in Rayleigh damping if I have the damping ration and M and K (let's say just scalar ), at least in a range, using a MATLAB function etc ?

[KSSV]

C = a*M+b*K ;

You know C,M, K...you can fix either a or b and get the other value.