I have this equation with complex parameters m and e (k is constant):

sqrt(m/e)*tanh(i*k*sqrt(m*e))=1

and I know that if imag(m)>3*real(m) and real(e)>3*imag(e)

the solution is approximated by the equations:

imag(m)=1/k
and
real(e)=3*real(m)

but I can't understand why.

Is there anyone that can help me?

thank you in advance!