like if you want to approximate e you just evaluate this as x is equal to one so this is, well, so you just say e is e ^ 1 and this is going to be approximately equal to this polynomial evaluated at 1 if x is 1 here, then we make x equal to one over here so it will be, one plus one plus one over 2! plus one over 3! plus one over 4! and so on and so forth all the way into infinity and you could also do this as one over 1 ! as well but what's really cool is that this is another way to represent e it shows that e once again shows up as kind of 2 + 1/2 + 1/6 if you keep doing this, you get close to the number e but that by itself isn't the only fascinating thing if we look back at the Maclaurin Representation of these other functions. cosine (x)