# Thread: How do I find the inverse of this function?

1. ## How do I find the inverse of this function?

y = 5x^3 - x^5

I know that you switch the y and x values around, so the new equation is:

x = 5y^3 - y^5

However, I don't know what to do next in order to isolate y. Any suggestions would be greatly appreciated. Thank you in advance!

2. ## Re: How do I find the inverse of this function?

y can not be isolated here.

3. ## Re: How do I find the inverse of this function?

Originally Posted by misiaizeska
y = 5x^3 - x^5
I know that you switch the y and x values around, so the new equation is:
x = 5y^3 - y^5
However, I don't know what to do next in order to isolate y. Any suggestions would be greatly appreciated. Thank you in advance!
If only you would plot this function, you would see there is no inverse.

4. ## Re: How do I find the inverse of this function?

Originally Posted by Plato
If only you would plot this function, you would see there is no inverse.
May I ask how you know from that graph that there is no inverse? Does it have to be bijective?

5. ## Re: How do I find the inverse of this function?

Only bijective functions have inverses