Solution 33851: Calculating the Inverse of a Function using the TI-Nspire™ CAS Family Products.
How do I calculate the inverse of a function using the TI-Nspire CAS family products?
There is not a way to directly calculate the inverse of a function
using the TI-Nspire family products; however, there is a work around if
using the TI-Nspire CAS family products.
For example: Find the inverse of f(x) = 5/x+10 follow the steps listed below.
1) [f] [(] [x] [)] [: =]  [/] [x] [+]  
2) [menu] [3: Algebra] [1: Solve]
3) [f] [(] [y] [)] [=] [x] [,] [y] [Enter]
So, f -1(x) = 5/x-10.