Publishing an almost trivial paper to arxiv
Since you think of the work as trivial there is only one reason I can think of for publishing it. If, for some reason you need to make a reference to the material it contains, then it might be useful to have it in a public repository. Of course, you could, in most cases, make reference to the source material instead, or simply incorporate the work into something more significant. But if, for example, you want to void the problem of cross referencing between other papers this might be a good idea. 

Otherwise, it might be better to sit on the result until you have something of substance.