Find the coordinates of the first inflection point to the right of the origin:

I think that it's obvious that I have to find the second derivative of Si(x) and then set it equal to zero. Here is what I did:

Let

(according to FTC1)

Assuming all is well to here (big assumption, I know), I get stuck on solving for zero:

When I graph this on my calculator, there isn't an obvious solution.

For whatever it's worth, my calculator tells me that the answer to this is approximately

Anybody see where I am going wrong or have a suggestion to get me unstuck?

Thanks.