Well obviously both of these terms have an e to the negative 2x squared. So I'm going to try to figure out where this is either undefined or where this is equal to 0. So let's think about this a little bit. So let's see, if we factor in e to the negative 2x squared, I'll do that in green, we're going to have, this is equal to e to the negative 2x squared times, we have here 1 minus 4x squared. So this is the derivative of f. Now, where would this be undefined or equal to 0? Well, let's see, e to the negative 2x squared, this is going to be defined for any value of x. This part is going to be defined, and this part is also going to be defined for any value of x.