# Electric field generated by disk and conductor

I'm trying to solve the following problem but I have some doubts.

I have a disk of radius $$R$$ with charge $$Q$$ (positive) and, at distance $$d$$, an uncharged conductor (of radius $$R$$ as well). Both are centered at the same axis.

Supposing $$R$$ is very big compared to the considered distances, I'm asked about the electric field $$\vec E$$ between the disk and the conductor, inside the conductor, and above it.

I know, since $$R$$ is big, I can approximate the disk as an "infinite" plane, so $$\vec E$$ will be uniform. In that case, it's easy to calculate the field caused by the disk alone. But total $$\vec E$$ will be $$\vec E_{\text{disk}} + \vec E_{\text{conductor}}$$ and I can't figure out how to find this last one.

Here's what I'm talking about if it's not so clear (my english may not be very good).

Any help would be appreciated.