Is the function f increasing or decreasing in this direction at the given point?

It depends what function's graph you are talking about. If (at that point) the function is positive, then it is increasing, and if it is negative, then it is decreasing. Be careful, though. I'm not talking about whether or not the whole function is positive or negative, just that specific part of the graph. If you would like a more specific answer, please include which part of what function's graph you are talking about.