Evaluate I = ∫24 ∫23 (y² + 6) dy dx over the rectangle 2 ≤ x ≤ 4, 2 ≤ y ≤ 3.
Multivariable calculus worksheet with answers
1.Easy
f = y² + 62 ≤ x ≤ 42 ≤ y ≤ 3
I =
2.Easy
Evaluate I = ∫23 ∫01 (4xy² + 1) dy dx over the rectangle 2 ≤ x ≤ 3, 0 ≤ y ≤ 1.
f = 4xy² + 12 ≤ x ≤ 30 ≤ y ≤ 1
I =
3.Medium
For f(x, y) = 2x³e2y, find the directional derivative Duf at (1, 1) in the direction of v = (−4, 4).
f(x, y) = 2x³e2yP = (1, 1)v = (−4, 4)
Duf =
4.Medium
z = 4x²y³ + 3x³ + 2y³ + 2xy with x = −2t − 1 and y = t² − 1. Use the chain rule to find dz/dt at t = −1.
z = 4x²y³ + 3x³ + 2y³ + 2xyx = −2t − 1y = t² − 1t = −1
dz/dt =
5.Hard
f(x, y) = x³ + y³ + 9xy has a critical point at (0, 0). Compute the discriminant D = fxxfyy − fxy² there.
f(x, y) = x³ + y³ + 9xyP = (0, 0)
D =
6.Hard
The marked points are the critical points of f(x, y) = −x³ + 12x − y² − 6y. Click the local maximum.
f(x, y) = −x³ + 12x − y² − 6y
- 1A (2, −3)
- 2B (−2, −3)
Answer key
- 1. I = 24.67
- 2. I = 4.333
- 3. Duf = −10.45
- 4. dz/dt = −22
- 5. D = −81
- 6. A (2, −3)
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