Duplicate screen not working

I have a dell monitor and a panasonic tv, i have the monitor plugged into the graphics card (GTX 645) and the tv plugged into the integrated graphics (intel 4600) and when I press win+P and select duplicate the tv goes black but my monitor stays fine, when i right click and go to "screen resolution" it only has the extend option and the "only on screen 1" and "only on screen 2" options. is there any chance its because i'm using 2 different graphics devices or are they just not compatible? (i'm pretty sure that i have the latest drivers)

because the card has an hdmi a display port and a dvi, i have the monitor plugged in the hdmi and i have a long hdmi cable going to the tv since the only other hdmi port is the integrated graphics i just plugged it in there.

thanks

thanks everybody! I don't know if i will mess with a adapter, i was just making sure because i didn't know if i could w/o an adapter. thanks again!