xy + Let f: R2 → R where f(x, y) = 0 if (x, y) = (0,0) and f(x, y) = 72²² if (x, y) = (0,0). (a) Prove that Duf (0,0) = 0 if u = (1,0). (b) Prove that Duf(0, 0) = 0 if u = (0, 1). (c) Prove that Duf(0, 0) does not exist if u = (a, b) where ab 0. (d) Prove that Df(0, 0) does not exist (this can be done by proving that f is not continuous at (0, 0)).

Calculus For The Life Sciences
2nd Edition
ISBN:9780321964038
Author:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Publisher:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Chapter14: Discrete Dynamical Systems
Section14.3: Determining Stability
Problem 13E: Repeat the instruction of Exercise 11 for the function. f(x)=x3+x For part d, use i. a1=0.1 ii...
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Real Analysis II Please solve 1b,c&d
1. Let f: R² → R where f(x, y) = 0 if (x, y) = (0,0) and f(x, y) = 724 44²
if (x, y) = (0,0).
(a) Prove that Duf(0, 0) = 0 if u = (1,0).
(b) Prove that Duf (0,0) = 0 if u = (0, 1).
(c) Prove that Duf(0, 0) does not exist if u = (a, b) where ab ‡0.
(d) Prove that Df(0, 0) does not exist (this can be done by proving
that f is not continuous at (0, 0)).
1) Fix 4³0. chrose 8 = [E] Assume Q = ||| < 8. Then || = [F(t,0) - f(0,0)] - 0 ||
-11/12-07-011=0 < 2₁₁
city=(1₁0)
L₁: (0,0) (0) = 0 Lufe - 0 | (0,0) 0
1) Fix 2-0. Choose S-1. Assume 0= 111 < S. Then 11 = [f(0, 1) - ((0,0)] - 011
+ 1/[0] = 011=0 < E c+t₁ = (0₁1)
L: (0,0)(1)-0 Lake 0/(0,0) = 0
Sikunt: ((t,0)=
+ (0) = ²0
0
((0,¹) 07:0
f =
1
+ 1²
2)si catus (at, bt) f(at, b1) = _abt
45²
¥² (₁²-b²) ₁²-6₂²
=
LEH COM
Transcribed Image Text:1. Let f: R² → R where f(x, y) = 0 if (x, y) = (0,0) and f(x, y) = 724 44² if (x, y) = (0,0). (a) Prove that Duf(0, 0) = 0 if u = (1,0). (b) Prove that Duf (0,0) = 0 if u = (0, 1). (c) Prove that Duf(0, 0) does not exist if u = (a, b) where ab ‡0. (d) Prove that Df(0, 0) does not exist (this can be done by proving that f is not continuous at (0, 0)). 1) Fix 4³0. chrose 8 = [E] Assume Q = ||| < 8. Then || = [F(t,0) - f(0,0)] - 0 || -11/12-07-011=0 < 2₁₁ city=(1₁0) L₁: (0,0) (0) = 0 Lufe - 0 | (0,0) 0 1) Fix 2-0. Choose S-1. Assume 0= 111 < S. Then 11 = [f(0, 1) - ((0,0)] - 011 + 1/[0] = 011=0 < E c+t₁ = (0₁1) L: (0,0)(1)-0 Lake 0/(0,0) = 0 Sikunt: ((t,0)= + (0) = ²0 0 ((0,¹) 07:0 f = 1 + 1² 2)si catus (at, bt) f(at, b1) = _abt 45² ¥² (₁²-b²) ₁²-6₂² = LEH COM
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