I'll try to leave, actually, I'll leave this little visualization here. So let's see, f prime, f prime of x is going to be 1.5 x to the negative 1.5, just using the power rule over here. So f prime of four, f prime of four is equal to 1.5 times four to the negative 1.5, which is of course equal to 1.5 times 1.5. Four to the 1.5 would be two, four to the negative 1.5 is going to be 1.5. So this is equal to 1.4. So L of, we deserve a little bit of a drum roll now, L of 4.36 is equal to f of four, it's equal to f of four, which is, let me just rewrite it, it's f of four plus f prime of four plus, gee, why am I switching to that color? Let me do the yellow.