# Is #f(x)=x^4-2x^3-9x-14# concave or convex at #x=-1#?

##### 1 Answer

Dec 25, 2015

At **Convex** or **Concave Up** Explanation given below.

#### Explanation:

Step 1: **Find the derivative**

Step 2: **Differentiate again with respect to x**

Step 3: **Substitute #x=-1# in #f^2(x)# and check for sign**

**If** **then** the curve is convex.

**If** **then** the curve is *concave *

We can see at **convex**.

For further information, you can refer

Note: Concave up is same as convex and concave down is concave

http://tutorial.math.lamar.edu/Classes/CalcI/ShapeofGraphPtII.aspx