Now that we have explored derivatives, we can now progress to the rules of differentiation. These rules are simply formulas that instruct the learner how to compute derivatives depending on a given function.
A useful rule of differentiation is the sum/difference rule. The rule is
This rule simply tells us that the derivative of the sum/difference of functions is the sum/difference of the derivatives. Consider the following graphs and respective functions as examples.
The following graph illustrates the function 
and
its derivative 
.
The following graph illustrates the function 
and
its derivative 
.
