I'm getting spoonfed instructions and I still don't get it. >_>
I am to find the inverse of f(x) = x^3 + x, by using properties of sinh(x).
The question tells me to let y = x^3 + x, let z = and then prove that .
After I do that, it tells me to set z = sinh(θ), solve for θ and then reverse the changes to the variables to find x as a function of y.
I managed to do most of it, up until the 'reverse the changes' part. My θ equals something ridiculously long and confusing, and I have no idea how to use it to my benefit.
Just need a bit of guiding light, it feels like I overlooked something...
EDIT: All right, well, I solved for θ in terms of x now too.
And then I equate the two.
And I'm not exactly sure how to solve...