Recognize a product of two vars in Mathematica?

[eNaught]

I am wondering if anyone can tell me how to get Mathematica to recognize the product of two variables so that I can do things like take limits. For example, if I had a function F[x] = x*(R*W)^2 + 4*x and I want Mathematica to take the limit as (R*W)->0, how can this be done? I realize this example is very trivial but I am just trying to explain what I want to do. Thanks in advance.

 

[jgm340]

In your case, the simplest thing to do is replace (R*W) with some variable (say t). Then you just take Limit[x*t^2 + 4*x, t -> 0]. In your example you are only really taking a one dimensional limit, after all.

If you do need to take a multidimensional limit, you say:

Limit[x*(R*W)^t + 4*x, {R,W} -> {0,0}