Evaluate I = ∫12 ∫23 (−2y + 2) dy dx over the rectangle 1 ≤ x ≤ 2, 2 ≤ y ≤ 3.
Multivariable calculus worksheet with answers
1.Easy
f = −2y + 21 ≤ x ≤ 22 ≤ y ≤ 3
I =
2.Easy
For f(x, y) = −y·e2xy, find the mixed second partial derivative ∂²f/∂x∂y at (0.5, 2).
f(x, y) = −y·e2xyP = (0.5, 2)
fxy(0.5, 2) =
3.Medium
The tangent plane to z = 2x³y + 4x³ − 3xy at the point where (x, y) = (1, −1) can be written as z = px + qy + c. Find c.
f(x, y) = 2x³y + 4x³ − 3xy(a, b) = (1, −1)
c =
4.Medium
The tangent plane to z = 3 sin(x + 3y) at the point where (x, y) = (0.5, −1) can be written as z = px + qy + c. Find c.
f(x, y) = 3 sin(x + 3y)(a, b) = (0.5, −1)
c =
5.Hard
Find the critical points of f(x, y) = x⁴ + y⁴ − 16xy, classify them, and give the value fmin of f at its local minimum.
f(x, y) = x⁴ + y⁴ − 16xy
fmin =
6.Hard
Find the critical points of f(x, y) = x³ − 27x + y², classify them, and give the value fmin of f at its local minimum.
f(x, y) = x³ − 27x + y²
fmin =
Answer key
- 1. I = −3
- 2. fxy(0.5, 2) = −118.2
- 3. c = −5
- 4. c = −7.804
- 5. fmin = −32
- 6. fmin = −54
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