关键词 > Math/Mthe280
Math/Mthe 280 Fall 2022 Problem Set 2
发布时间:2022-09-14
Hello, dear friend, you can consult us at any time if you have any questions, add WeChat: daixieit
Math/Mthe 280
Fall 2022
Problem Set 2
1) Let f : R3 → R be defined by,
f (x, y, z) = 3x - 5y + 2z.
a) Prove by using an e-6 definition the following limit,
lim f (x, y, z) = 19.
(x,y,z)→ (1, -2,3)
b) Is the function f continuous at (1, -2, 3)?
2) Compute the partial derivatives and
for the following functions,
a) f (x, y) = xy2 + x2y
b) f (x, y) = ex2 +y2
c)
f (x, y) = ¥. x2 + y2 , if (x, y)
(0, 0)
¥( 0, if (x, y) = (0, 0)
For this one be careful with partial derivatives at (0, 0).
3) Let f : R2 → R be defined by,
f (x, y) = ^3xy.
a) Prove that both, (0, 0) and
(0, 0) exist and compute them.
b) Is f differentiable at (0, 0)?