Only questions 39 part a, and 43 part a.

Linearizations for Three Variables Find the linearizations L(x, y, z) of the functions in Exercises 39- the given points. 39. f(x, y, z) = xy + yz + xz at a. (1, 1, 1) b. (1, 0, 0) c. (0, 0, 0) 40. f(x, y, z) = x2 + y2+ z at a. (1, 1, 1) b. (0, 1, 0) c. (1, 0, 0) 41. f(x, y, z) = Vx2 + y2 + z at a. (1, 0, 0) b. (1, 1, 0) C. (1, 2, 2) 42. f(x, y, z) = (sin xy) /z at a. (TT / 2, 1, 1) b. (2, 0, 1) 43. f(x, y, z) = ex + cos (y + z) at a. (0, 0, 0) b. 0, TT C. 0, TT TT 4 4 fly v 7) tan -1 TV7)