Section 2.4

Memorize the product and quotient rules in words, not symbols. See the italicized sentence above example 1 and the italicized sentence above example 3.

You are not responsible for knowing the reciprocal rule in the green box above the Summary of Differentiation Rules on p. 167.

You do not need the product rule unless both factors in the product contain a variable. Specifically, you do not need the product rule to differentiate y = 3x². Since 3 is a constant, we use the Constant Multiple Rule (Theorem 2.3.4 in the last section). Similarly, we do not need the quotient rule unless both the numerator and denominator contain a variable. Specifically, we do not need the quotient rule to differentiate

The first can be rewritten as

And the second can be rewritten as

both of which can be differentiated by the methods of the previous section.