Section 3.3 The Product and Quotient Rule. Consider the function –What is its derivative? –What...

7
Section 3.3 The Product and Quotient Rule

Transcript of Section 3.3 The Product and Quotient Rule. Consider the function –What is its derivative? –What...

Page 1: Section 3.3 The Product and Quotient Rule. Consider the function –What is its derivative? –What if we rewrite it as a product –Now what is the derivative?

Section 3.3The Product and Quotient Rule

Page 2: Section 3.3 The Product and Quotient Rule. Consider the function –What is its derivative? –What if we rewrite it as a product –Now what is the derivative?

• Consider the function– What is its derivative?– What if we rewrite it as a product– Now what is the derivative?

• So if f and g are differentiable functions we have (fg)’ ≠ f ’g’

• Thus we come to another rule

6xy

42 xxy

Page 3: Section 3.3 The Product and Quotient Rule. Consider the function –What is its derivative? –What if we rewrite it as a product –Now what is the derivative?

Theorem 3.3: Product Rule

• If u = f(x) and v = g(x) are differentiable, then

(fg)’ = f ’g + f g’• The product rule can also be written

• “The derivative of the product is the derivative of the first times the second plus the derivative of the second times the first”

dx

dvuv

dx

du

dx

uvd

)(

Page 4: Section 3.3 The Product and Quotient Rule. Consider the function –What is its derivative? –What if we rewrite it as a product –Now what is the derivative?

Examples

3

3

2

)(

)5)(43(2)(

)9()(

3)(

x

exj

xxxh

exxxg

exxf

x

x

x

x

Page 5: Section 3.3 The Product and Quotient Rule. Consider the function –What is its derivative? –What if we rewrite it as a product –Now what is the derivative?

• Just like with products, we have a similar rule for quotients

• In fact we can derive the rule from our product rule

Page 6: Section 3.3 The Product and Quotient Rule. Consider the function –What is its derivative? –What if we rewrite it as a product –Now what is the derivative?

Section 3.4: Quotient Rule

• If u = f(x) and v = g(x) are differentiable, then

• The quotient rule can also be written

2

/''

g

fggf

g

f

2vdxdv

uvdxdu

v

u

dx

d

Page 7: Section 3.3 The Product and Quotient Rule. Consider the function –What is its derivative? –What if we rewrite it as a product –Now what is the derivative?

Examples

3

2

3

1

5)(

)(

x

xxxg

x

exf

x