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.
When differentiating trigonometric functions, special differentiation rules apply. They are:
To illustrate derivatives of trigonometric functions, consider the following functions and their respective derivatives. It is suggested that you compute the derivative to verify the function of the derivative.
The following graph illustrates the function y=sin(3x) and its derivative y'=3cos(3x).
The following graph illstrates the function 
and its derivative 
