Or you could go a little bit further, you could take the second derivative, you, let's do that, just for kicks. So we could take the second derivative of our acceleration function. So this is going to be equal to negative six, right? So the derivative of negative six t is negative six, the derivative of constant is just zero. So this thing, the second derivative is always negative. So we are always, always concave, concave downward, downward. And so by the second derivative test, at t equals two, well at t equals two, our second derivative of our acceleration function is going to be negative.