Okay, I must pipe in with my 2=A2 worth. Back in college, I recall solving some problem for frequency. I ended up=20 with a quadratic and as we know, there are two answers in the solution of a= =20 quadratic. It turns out one answer was positive frequency and the other=20 was negative frequency. Negative frequency??? We've always been taught to simply "throw away" the "nonsensical" or=20 "nonphysical" answer in these cases but does this mean they arent "true" in= =20 some sense? (One prof talked about anti-matter and negative frequency=20 being related in some guise...yikes!) Another example from college involved solving for a particular resistor=20 with in a network of resistors (typical torture problem from an eccentric=20 professor). The final function was a quadratic and you ended up with a=20 positive resistance and a negative resistance as solutions. Negative resistance??? This one isn't so far fetched. Gunn diodes take advantage of the region is= =20 which their I/V plot is negatively sloped. Oscillators are made taking=20 advantage of this. In the end, I have concluded that Mathematics is simply (and usually) an=20 elegant way to get a grasp (i.e. model, represent) on our physical=20 environment and it isn't perfect. After all, don't most of us take=20 Maxwell's Equations as gospel? ;^) Chris Padilla EMC Engineer Cisco Systems ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu