190 likes | 290 Views
UNIT 2 LESSON 5. QUOTIENT RULE. If you thought the product rule was bad. Function f is the QUOTIENT of functions g and h. It would be nice if the rule were. But, it is NOT!!!. Example 1 Let’s show that if f ( x ) = x 3 + x 2 – 5 x and g ( x ) = – x then. then. =. and.
E N D
UNIT 2 LESSON 5 QUOTIENT RULE
Functionfis the QUOTIENT offunctionsgandh It would be nice if the rule were But, it is NOT!!!
Example 1 Let’s show that if f(x) = x3 + x2 – 5x and g(x) = – x then then = and
Example 1 continued If and and so ≠ From previous slide then
Quotient Rule In this section we develop a formula for the derivative of the quotient of two functions.
Let’s try it in English The bottom (g (x)) times the derivative of the top f′ (x) minus the top (f (x)) times the derivative of the bottom g′ (x) all over the bottom g(x) squared.
Example 1 continued FROM BEFORE if and then Quotient Rule x ≠ 0
EXAMPLE 2 Iff(x) = x2 + 3x + 2 andg(x) = x + 1 then
Example 2 continued Usef(x) = x2 + 3x + 2 andg(x) = x + 1 to show that ≠ but from previous slide
Example 2 continued Usef(x) = x2 + 3x + 2 andg(x) = x + 1 to show that and from previous slide =
Differentiate. State any restrictions on the domain. Example 3 Using the Quotient Rule Restriction on domain x ≠ 4
Differentiate . State any restrictions on the domain. Example 4 Using the Quotient Rule Since x2 + 1 is always > 0 there are no restrictions
Example 6 Using the Quotient Rule Differentiate using the Quotient Rule.
Example 6 continued Find the slope of the tangent at P(0, ½ ) From previous slide
At what points on the curve is the tangent line horizontal? Example 7 Application The tangent line will be horizontal when the derivative = 0 2x(x + 5) = 0 x = 0 or x = -5 Points are (0, 0) and (-5, -5)
Example 7 Application (0, 0) y = 0 y = -5 (- 5, - 5)
Complete Homework Assignment Questions 1-5