Search for notes by fellow students, in your own course and all over the country.

Browse our notes for titles which look like what you need, you can preview any of the notes via a sample of the contents. After you're happy these are the notes you're after simply pop them into your shopping cart.

My Basket

You have nothing in your shopping cart yet.

Title: Find the differentiation or derivative of an inverse function
Description: Basic concept on how to differentiate the inverse of a function with solved examples. Proof of the formula for finding the derivative of an inverse function.

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above


Find the derivatives of inverse functions
...

f ( x)  y  x  f

1

( y)
...
If f
inverse of f (x ) , then f 1 ( x) is differentiable at any x and

f

1



( x)  

where

f

1

1

( x) denotes the

1
f [ f

1

( x)]



( x)  denotes the derivative of inverse of f (x ) , f (x ) is the derivative of



f (x ) and f  f

1



( x)  0
...


Differentiating f [ f 1 ( x)]  x applying chain rule:

df [ f 1 ( x)] dx

dx
dx
df [ f 1 ( x)]
df [ f 1 ( x)] df 1 ( x)
df 1 ( x)
 f  [ f 1 ( x)] and

 1 , but
 [ f 1 ( x)]
dx
dx
df 1 ( x)
df 1 ( x)
Thus f [ f 1 ( x)] [ f 1 ( x)]  1
Dividing equation (1) by f  [ f
[ f 1 ( x)] 

1
f  [ f 1 ( x)]

1

equation (1)
( x)] ,

, where [ f 1 ( x)] is the derivative of the inverse of f (x ) and

f [ f 1 ( x)]  0
...


[ f 1 ( x)] can be represented as [ f 1 ]( x)
...
If f ( x)   x 3  2 x  3 , find the derivative of the inverse of f (x ) denoted by,
[ f 1 ]( x) when x  1
...

[ f 1 ( x)] 

1

and

f  [ f ( x)]
1

f ( x)  3x 2  2
...


f ( x)  y  x  f

1

Applying the power rule,

( y) and the inverse of an order pair (x, y) is

(y, x)
...

Solving f ( x)  1 , we have  x 3  2 x  3  1
 x 3  2 x  4  0
...
for x,

 (1) 3  2(1)  4  0 ,  (1) 3  2(1)  4  0 ,

 0 3  2(0)  4  0 ,
 (2) 3  (2)  4  0 ,

 (2) 3  (2)  4  0 , x  2
...

[ f 1 (1)] 

1
f  [ f (1)]
1

, but f 1 (1)  2
...

[ f 1 (1)] 

1
1
1


...
Find [ f

1

...

[ f 1 ( x)] 

1
f  [ f 1 ( x)]

f ( x)   sin x
...


and

f ( x)  y  x  f

1

( y) and the inverse of an order pair (x, y) is

(y, x)
...


1
2

f 1 ( 1 )  cos 1 1 
2
2

, but f 1 ( 1 ) 
2


3


3


...

3

Example 3
...

Solution
...

f [h(2)]

f ( x)  x 4  x 3
...


f ( x)  y  x  f 1 ( y)
...
It implies the inverse of the ordered pair (2 ,y) is (y , 2)
...
Substituting the values 0 ,  1 ,  2 ,  3
...

[ f 1 (2)] 

1
f  [ f (2)]
1



1
, but f
f [h(2)]

1

(2)  1  h(2)
...

h (2) 

1
1

...

7

1
f  (1)


Title: Find the differentiation or derivative of an inverse function
Description: Basic concept on how to differentiate the inverse of a function with solved examples. Proof of the formula for finding the derivative of an inverse function.