What is the Sum Rule for derivatives?
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.