OS X Yosemite: Use your TV as a display
Many televisions can also be used as computer displays. To connect your Mac to your television, you need a video cable that connects your computer’s display port to your TV. If you can’t find a cable that connects the ports on your Mac and TV, you may also need an adapter for the cable.
If you have an HDTV and a Mac with a Thunderbolt port , Mini DisplayPort , or HDMI port, the cable could also let you play your computer’s audio on your TV.
Check whether the display port on your Mac sends audio
If your Mac has a Thunderbolt or HDMI port: It can send audio to your HDTV.
If your Mac has a Mini DisplayPort: It may be able to send audio to your HDTV. To find out, choose Apple menu > About This Mac. In the window that appears, click Overview, then click the System Report button.
In the window that appears, select Audio (Built In) below Hardware in the Contents list.
A list of your computer’s audio devices appears. If HDMI Output or HDMI/DisplayPort output is listed, your computer’s Mini DisplayPort can send audio.
Connect your Mac to your TV
Connect the video cable (and adapter, if necessary) from the computer’s Thunderbolt port , HDMI port, or DVI port to the TV’s video input port.
If you want your HDTV to play audio as well as video from your Mac, choose Apple menu > System Preferences, click Sound, then click Output.
Select your HDTV or the AV receiver that is part of your sound system in the list of devices.Note: If your Mac has a Mini Display port , make sure you use a cable (and adapter, if necessary) that supports both audio and video.