Calculus help please! thanks so much!?

Spruce budworms are a major pest that defoliate balsam fir. They are preyed upon by birds. A model for the per capita predation rate is given by f(N) = aN / (k^2 + N^2) where N denotes the density of spruce budworm and a and k are positive constants. Find f ' (N) and determine where the predation rate is increasing and where it is decreasing.

Calculus help please! thanks so much!?
f'(N)


= [a(k^2 + N^2) - 2aN^2] / (k^2 + N^2)^2


= a[k^2 - N^2] / (k^2 + N^2)^2


If k %26gt; N, f'(N) %26gt; 0 =%26gt; Increasing


If k %26lt; N, f'(N) %26lt; 0 =%26gt; Decreasing