# What is the Sum Rule for derivatives?

##### 1 Answer

*The sum rule for derivatives states that the derivative of a sum is equal to the sum of the derivatives.*

In symbols, this means that for

we can express the derivative of

For an example, consider a cubic function:

Note that A, B, C, and D are all constants. Now we will make use of three other basic properties, two of which are illustrated together below, without proof.

The third is the **Power Rule**, which states that for a quantity

Using all four of these properties, we can find the derivative of our cubic expression.