Calculus Inverse Functions

In summary, the conversation discusses finding the inverse of a function and computing its derivative at a specific point. The first step is to switch the variables x and y, and then show that the function is increasing. It is also important to test the function with a simple case to ensure the correctness of the solution. Finally, a function must be one-to-one and have a unique output for every input to be invertible.
  • #1
alexs2jennisha
14
0

Homework Statement



1. Show that the function f(x) = x5 -x3 +2x is invertible. Compute the derivative of f-1
at 2.


The Attempt at a Solution


To find f-1 I switched x and y which gave me x = y5 - y3 + 2y

this is where i got stuck because I am not sure how to solve for y after that step.

Can the y5 - y3 become y2?

Thanks
 
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  • #2
alexs2jennisha said:

Homework Statement



1. Show that the function f(x) = x5 -x3 +2x is invertible. Compute the derivative of f-1
at 2.


The Attempt at a Solution


To find f-1 I switched x and y which gave me x = y5 - y3 + 2y

this is where i got stuck because I am not sure how to solve for y after that step.
Lucky for you, you weren't asked to calculate ##f^{-1}##, just show it exists. Can you show, for example, that ##f## is increasing?
Can the y5 - y3 become y2?

Of course not.
 
  • #3
alexs2jennisha said:
Can the y5 - y3 become y2?

one really good way to see if numeric algebra works is to take a simple case and see what happens. what if [itex]y=1[/itex]?? then you know the answer to be zero yet if you adopt your proposition we see the answer is 1, which is of course incorrect.

hope this helps for the future
 
  • #4
What is necessary for a function to be invertible ?
 

1. What is an inverse function in calculus?

An inverse function in calculus is a function that reverses the input and output relationship of another function. In other words, if a function takes an input, the inverse function will take the output and vice versa.

2. How do you find the inverse of a function in calculus?

To find the inverse of a function in calculus, you can follow these steps: 1) Rewrite the function as y = f(x), 2) Switch the x and y variables, 3) Solve for y, 4) Replace y with f-1(x) to represent the inverse function.

3. What is the domain and range of an inverse function in calculus?

The domain of an inverse function in calculus is the range of the original function, and the range of an inverse function is the domain of the original function. In other words, the x-values of the inverse function will be the y-values of the original function, and vice versa.

4. Can any function have an inverse in calculus?

No, not all functions have an inverse in calculus. For a function to have an inverse, it must be one-to-one, meaning that each input has a unique output. This can be determined by using the horizontal line test.

5. How do you graph the inverse of a function in calculus?

To graph the inverse of a function in calculus, you can reflect the points of the original function across the line y = x. This will result in a graph that is a mirror image of the original function's graph. Additionally, the domain and range of the inverse function will be the same as the range and domain of the original function, respectively.

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