This is the limit as x approaches pi over two of sine of x over cosine of x. Now sine of pi over two is one, but cosine of pi over two is zero. So if you were to just substitute it in, this would give you one over zero. And one way to think about it is, pi over two is not in the domain of tangent of x. And so this limit actually turns out it doesn't exist. In general, if we're dealing with sine cosine tangent or cosecant secant or cotangent, if we're taking a limit to a point that is in their domain, then the value of the limit is going to be the same thing as the value of the function at that point. If you're taking a limit to a point that's not in their domain, there's a good chance that we're not going to have a limit.