The important thing to realize then is well, if over here it's negative, then over this whole interval, because it's not crossing through zero or it's not discontinuous at any of these points, that's why we picked this interval, that over this whole interval, g prime prime of x is less than zero, which means that over this interval we are concave downwards. So concave, concave downward, concave downward. Now let's go to the interval between negative one and one. So this is the open interval between negative one and one. And let's try a value there. Let's just try zero will be easy to compute. G prime prime of zero.