Hi, for this problem do I move Z to the other side of the equation before solving? z=f(x,y) and (x,y)=(0,1) and f(0,1)=1 so (x,y,f)=(0,1,1). Should I solve for the tangent plane using 0=f(x,y)-z and (0,1,1)? I did so by finding gradient f(x,y,z) at (0,1,1) using that as my normal vector, and the point (0,1,1) I got x+2y-z+3 as my tangent plane equation. Should I have solved it only in terms (x,y)?
(b)Find the equation for the tangent plane to the graph of z =f,y=ye at 0,1. Use this equation to approximate f(0.2,1.1)