Ok little of matlab helped. I stll havent solved the problem. but apparantly Lambart W function helps to solve this problem. http://mathworld.wolfram.com/LambertW-Function.html Also wikipedia gives one example http://en.wikipedia.org/wiki/Lambert's_W_function I got the following equation -1/2log2=xlog(1/root(2))exp(xlog(root(2)) or x/2log2=W(-log2/2) Apparantly W(-log2/2)=-log2 but W is supposed to be multivalued, now i didin get that but using W(-log2/2)=-log2 we can at least get x=2 Well if someone can crack this whole thing it will be cool.