Assignment on approximations for calculus

[Physics197]

I'm doing an assignment on approximations for calculus and I feel that I don't really have a strong background and was hoping that someone maybe has a website, or even a few pointers, so that I can better my understanding.

Right now I'm working on "Find two term approximations for the following functions at x = 0" questions.

Thanks

 

[LCKurtz]

Look at Taylor series in any calculus book. Or tons of places on the internet. One such is

http://en.wikipedia.org/wiki/Taylor_series