You can't "solve" a function. You can only graph it. You said it yourself, it's a sine wave that grows logarythmacilly (ok, the spelling went off at the end there(
You could solve and equation for x. For example, if we had the equation:

y = m*x+b

we could solve this for x, giving us:

(y - b) / m = x

I tried running the equation through my calculator, and I could not get a solution.