Find the equation of the tangent plane to z=x2yz = x^2 yz=x2y at (1,1,1)(1, 1, 1)(1,1,1).
2x+y−z=22x + y - z = 22x+y−z=2
x+2y−z=2x + 2y - z = 2x+2y−z=2
2x+y−z=02x + y - z = 02x+y−z=0
x+y−z=1x + y - z = 1x+y−z=1