Things You'll Need
Instructions
Avoid the gunner's shots wherever possible; if you have a choice between hitting the tank and avoiding being hit, avoid being hit.
Watch for the turret to pop up at the top of the tank; when this happens, whichever character's box is not flashing red has only a few moments to hit that turret with a rocket.
Done correctly, this will stop the tank firing at you.
Destroy every last piece of the tank's armor, including the wheels, the front and back, and the sides. Only then will you defeat it.