3.8 Derivatives of Inverse Functions Mon Nov 19

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Transcript 3.8 Derivatives of Inverse Functions Mon Nov 19

3.8 Derivatives of Inverse Functions Mon Oct 27 Do Now Find the inverse of each function 1) Y = 3x - 5 2) Y = x^4 + 10

HW Review: p.175 #1-85

Derivative of the Inverse • Assume f(x) is differentiable and

g

(

x

) =

f

1 (

x

) • And if f’(g(x)) is not 0 then

g

'(

x

) = 1

f

'(

g

(

x

))

Inverse Derivatives • We can use the previous theorem to find the derivative of an inverse • We can also find the inverse first and differentiate directly

Ex 2 • Calculate g’(1) where g(x) is the inverse of f(x) = x + e^x

Inverse Trig Derivatives • One of these six might appear on the

d dx

AP exam:

d dx d dx

sec sin 1 tan 1

x

-

x

= 1 = 1 1 -

x

2

x

=

x

2 1

x x

2 1 + 1 1

d dx d dx

cos 1

x d dx

cot 1

x

csc 1

x

= = = 1

x

2 1 1 + 1 1

x

2

x x

2 1

Closure • Calculate

d dx

csc 1 (

e x

+ 1) where x = 0

DO NOW • Find the derivative 2

e

sin 4 (

x

3 -

x

) -

x

2 tan

x