Is it possible to use a shark tooth connection to connect 1/2"copper tube to rigid plastic tubing on a water supply?

Hi Linwat...

YUP... if the plastic pipe is CPVC.

If not cpvc (creme color), but pvc (white color) then you would need to use a threaded sharkbite fitting as in the pictures below.

Here, you would use, for example, a male x sharkbite fittting (1st pic.) and then you would install a pvc female adapter... or vice versa.
You cannot use pvc pipe/fittings on hot water... ok?

Let me know if need more information... ;)