Hallo, Frank Barknecht hat gesagt: // Frank Barknecht wrote: > > 1*z^2 - fb1*z^1 - fb2 = 0 > zb = (-fb1 +- sqrt(fb1*fb1 - 4*fb2)) / 2 Sorry, the one above is wrong, of course. Given the minus-signs in the original transfer formula it should be: zb = (fb1 +- sqrt(fb1*fb1 + 4*fb2)) / 2 if I'm right. Ciao -- Frank