y = sin(x)*cos(z)+ x^2*z^2
for x = 0
z = 0
= 0 * 1 + 0^1*0^2
Thats the lowest (non-negitive) it can get.
If you need two different values,
x = 0
z = 1/infinity
Thats pretty much the same.
For negitive, the solution would probably -infinity for both x and z.
If both can't be the same, then -infinity for x, x - 1 for z.
As for ga's, you need to give em a better problem... (how about getting a ga to make an ann, thats about the best thing i've seen em do :-))
Either way, nice tutorial.
Any chance you can do something on simulated annealing. (its a nifty thing to use).