We have to be careful with those, make sure that they are indicative. And then we would say the sine of our second derivative of g prime prime. And then we would have our concavity, concavity of g. And in order for x equals zero to be an inflection point, we would have to switch sines as, or our second derivative would have to switch sines as we cross x equals zero, and which would mean our concavity of g switches sines as we go, as we cross x equals zero. So let's do values less than zero, negative infinity to zero, and then values greater than zero, infinity, zero to infinity. I could do test values, let's say, I'll use negative one and one. And you have to be careful when you use these, you have to make sure that we are close enough that nothing unusual happens between these test values up until we get to that candidate inflection point. And now what's the sine of our second derivative when x is equal to negative one?