You should answer part of this question in the group quiz. (L) Consider the function
f(x, y, z) = cos(πx)е³-²
(a) Evaluate the function at the point (1,1,1).
(b) Find the tangent plane to the function at this point.
(c) Use your tangent plane expression to give an approximation f(1.1, 1.1, 1.1).