# Is #f(x)=-3x^3-2x^2-12x-4# concave or convex at #x=-1#?

##### 1 Answer

May 27, 2016

Convex.

#### Explanation:

It is concave if the second derivative is less than zero and convex if the second derivative is greater than zero.

The first derivative is:

The second derivative is: -18x – 4 At x = -1 this is 14, so the original equation is convex at that point.

Weisstein, Eric W. "First Derivative Test." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/FirstDerivativeTest.html