Originally Posted by

**lysserloo** This problem has to do with the second derivative of a function. Here's the problem:

A function *f* has f(3) = 20, $\displaystyle f\prime(3) = 3$, and $\displaystyle f\prime\prime(x)$ > 0 for x > 3. Which of the following are possible values for f(5)? State why or why not.

a.) 26

b.) 24

c.) 22

**What I've Done So Far:** I attempted to graph f(x), because I know that the point (3 , 20) is on it, and the tangent line to that point has a slope of 2. I also know the graph is increasing, and is concave up from $\displaystyle (3 , \infty)$, implying that before that point, it's concave down (...right?). Having graphed it...I'm lost. I have no idea how to determine whether or not these are possible values. My best guess was to base it off of the slope (being 2). According to my poorly drawn graph, it doesn't *look like* b or c would be possible because of how the graph is increasing. But it seems incorrect to just eyeball it like that.

Any help would be greatly appreciated!