Find the equation of the tangent plane to z=x2+y2z = x^2 + y^2z=x2+y2 at (1,1,2)(1, 1, 2)(1,1,2).
z−2=2(x−1)+2(y−1)z - 2 = 2(x - 1) + 2(y - 1)z−2=2(x−1)+2(y−1)
z=x+yz = x + yz=x+y
z=x2+y2z = x^2 + y^2z=x2+y2
z−2=(x−1)+(y−1)z - 2 = (x - 1) + (y - 1)z−2=(x−1)+(y−1)