"ghasem " <shaban_sadeghi@yahoo.com> wrote in message <klur3t$nva$1@newscl01ah.mathworks.com>...
> hi.
> I want to find all of zeros following equation:
> t0*besseli(1,t1) * besselk(0,t0) + t1 * besselk(1 ,t0) * besseli(0,t1) = 0
> where:
> k0 is real constant and known.
> t0 and t1 are in terms of k:
> t1 = sqrt(k^2?r*k0^2)
> t0 = sqrt(k^2k0^2)
> k is unknown complex number ( k = k1 +j k2 )
> besseli and besselk are modified bessel functions of first and second type.
> in above equation,only unknown is k .
> now, i want to find zeros of above equation,i.e find " k " values.
> by using of solve command only one of the zeros are found.
> i can not use from fzero command,because I don't have any guess point that is imaginary(k) = k2 =0.
>
> i don't know how find all of zeros in this equation.
> this equation is a dispersion relation.
> is there someone who help me?
> ghasem
Hey, I am trying to solve a smiliar equation as that of above and having some difficulty. The equation is solvable but the answer is not correct. My equation is
f(x)=p/2/(2*v+1)*bessely(v,x)*(v*besselj(v1,N*x)(v+1)*besselj(v+1,N*x))(v*bessely(v1,x)(v+1)*bessely(v+1,x))*besselj(v,N*x)/(2*v+1)=0
this is basically a characteristic equation for eigen frequencies with v denoting the mode number. As I change v eigen frequency should change but it remains the same when I solve by using Fsolve. Please help me with some suggestions.
Thanks.
Nitesh
