Differentiating Trigonometric Functions
Derivative formulas through geometry | Chapter 3, Essence of calculus
3Blue1Brown video explaining some of the most common derivative formulas using geometry. Skip to 12 minutes and 36 seconds for an explanation into the derivative of the sine function.
In methods, we are note expected to memorize the rule for differentiating tan(x). Instead, we will use the quotient rule (which is explained further on in unit 3). This involves rewriting tan(x) as sin(x) divided by cos(x). This will be explored in more depth later on in unit 3.