Differential equations — practice question

Let $N$ represent the number of insects in the population at $t$ days after observations begin. The change in the insect count is described by the differential equation $\frac{dN}{dt} = k N^{\frac{3}{2}} \cos 0.02t$, where $k$ is a constant and $N$ is regarded as a continuous variable. It is also given that $N = 100$ when $t = 0$.