Is #f(x) =(x+2)^2+3x-3# concave or convex at #x=-2#?
1 Answer
Feb 2, 2018
Convex
Explanation:
To find the concavity, plug in -2 into the SECOND derivative, if you get a positive value, it is concave up (convex), if it's a negative, it's concave down.
The full equation is
First derivative:
Second derivative:
Well, they'res nothing to plug into the second derivative, so we take it for what it is. A positive means convex, and since the second derivative isn't effected by the x coordinate, that means the whole graph is concave, not just at x=-2