Inverse function

[elitewarr]

1. The problem statement, all variables and given/known data
Find the inverse function for f(x) = x + 4/x


2. Relevant equations



3. The attempt at a solution
I tried many times but just can't get the answer.
Is there any trick to this question?

Thank you

[CompuChip]

Basically, what you want to do, is solve
y = 4x + 4/x
for x.
Secretly, you can view this as a quadratic equation. You can either multiply through by x, then this becomes immediately apparent.

If you're looking for a more general approach, I suggest combining the two fractions (4x/1 and 4/x) on the right hand side into a single fraction A/B, then you can cross-multiply (y = A/B becomes yB = A).

In both cases, you can get an equation of the form
ax2 + bx + c = 0
the solution(s) of which give an inverse function.

[elitewarr]

Ahh!!! Why didn't I think of that. Thanks!