Pauls Online Notes are a great resource for everything calculus. If you need a refresher on anything calculus related, theres a page about it here. Not only that but there are also hundreds of problems for you to practice. There is even a section about differential equations if you are interested in learning more about how to solve them.
Its the best calculator on the internet. That is all.
It should also be pointed out that there is a Wolfram Alpha app (which can be found here. This app is available on all major devices, is relatively cheap and comes with a step by step calculator that can help you understand how to solve the problems you are assigned.
This is a really cool and accessible video on the logistic equation. It's presented with more enthusiasm than you'll likely see me display and it does a great job as to explaining why mathematicians are interested in dynamical systems independent from their applications. They'll be a binus problem on February 4ths quiz about this video as an incentive to watch it.