sudo add-apt-repository ppa:mactel-support && sudo apt-get update
sudo apt-get install bcm5974-dkms xserver-xorg-input-synaptics
sudo apt-get install xf86-input-multitouch bcm5974-dkms
setting the trackpad, edit xorg.conf (/etc/X11/xorg.conf), add following line in the end of xorg.conf file :
Section "InputClass"
MatchIsTouchpad "true"
Identifier "Multitouch Touchpad"
Driver "multitouch"
MatchDevicePath "/dev/input/event*"
EndSection
save it.