When x is greater than 2 thirds, what is f prime prime? What is the second derivative? So let's try out a value that's pretty close just to get a sense of things. So let me rewrite it. f prime prime of x is equal to 12x times 3x minus 2. So if x is greater than 2 thirds, this term right here is going to be positive. That's definitely, you know, any positive number times 12 is going to be positive.