Evaluate I = ∫12 ∫03 (3x·e−y) dy dx over the rectangle 1 ≤ x ≤ 2, 0 ≤ y ≤ 3.
Multivariable calculus worksheet with answers
1.Easy
f = 3x·e−y1 ≤ x ≤ 20 ≤ y ≤ 3
I =
2.Easy
Evaluate I = ∫13 ∫25 (4xy² + 4) dy dx over the rectangle 1 ≤ x ≤ 3, 2 ≤ y ≤ 5.
f = 4xy² + 41 ≤ x ≤ 32 ≤ y ≤ 5
I =
3.Medium
For f(x, y) = 2xy² − 2x² − 5y³ + 4xy, find the directional derivative Duf at P(−1, 2) in the direction towards Q(−4, 3).
f(x, y) = 2xy² − 2x² − 5y³ + 4xyP = (−1, 2)Q = (−4, 3)
Duf =
4.Medium
For f(x, y) = −3x²y² − 3x³ − 3y² + 2xy, find the maximum rate of change of f at the point (3, 3), that is |∇f|.
f(x, y) = −3x²y² − 3x³ − 3y² + 2xyP = (3, 3)
|∇f| =
5.Hard
Use polar coordinates to evaluate I = ∬R (x² + y²) dA, where R is the ring 1 ≤ x² + y² ≤ 4.
f = x² + y²1 ≤ r ≤ 20 ≤ θ ≤ 2π
I =
6.Hard
f(x, y) = x⁴ + y⁴ − 16xy has a critical point at (−2, −2). Compute the discriminant D = fxxfyy − fxy² there.
f(x, y) = x⁴ + y⁴ − 16xyP = (−2, −2)
D =
Answer key
- 1. I = 4.276
- 2. I = 648
- 3. Duf = −41.74
- 4. |∇f| = 294
- 5. I = 23.56
- 6. D = 2048
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