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8. Let f : R^3 → R a function all whose first order partial derivatives are continuous and such that f(0, 1, 1) = 0,

f_x(0, 1, 1) = 1, f_y(0, 1, 1) = 2, f_z(0, 1, 1) = 3. Find lim

t-->0

f(t2, cosh t, et)

f(t, cos t, cosh t)

9. Let f : R2 → R such that f(x, y) = f(y,−x) for all (x, y) ∈ R2, and f(2, y) = 2 + |y|. Then

A f_x(1, 2) = 1

B f_x(1, 2) = 0

C f_x(0, 2) = 1

D f_x(0, 2) = −1

E none of these

Hey. These are two problems on a practise test. I have no clue whatsoever how to do the first. My question for the second: does f(x,y) mean the same thing as f(y,x)?

Thanks so much.

f_x(0, 1, 1) = 1, f_y(0, 1, 1) = 2, f_z(0, 1, 1) = 3. Find lim

t-->0

f(t2, cosh t, et)

f(t, cos t, cosh t)

9. Let f : R2 → R such that f(x, y) = f(y,−x) for all (x, y) ∈ R2, and f(2, y) = 2 + |y|. Then

A f_x(1, 2) = 1

B f_x(1, 2) = 0

C f_x(0, 2) = 1

D f_x(0, 2) = −1

E none of these

Hey. These are two problems on a practise test. I have no clue whatsoever how to do the first. My question for the second: does f(x,y) mean the same thing as f(y,x)?

Thanks so much.

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