For f(x, y) = 3x²e3y, find the partial derivative ∂f/∂x at the point (−1, 0.5).
Multivariable calculus worksheet with answers
1.Easy
f(x, y) = 3x²e3yP = (−1, 0.5)
fx(−1, 0.5) =
2.Easy
Evaluate I = ∫24 ∫01 (6x²y + 2) dy dx over the rectangle 2 ≤ x ≤ 4, 0 ≤ y ≤ 1.
f = 6x²y + 22 ≤ x ≤ 40 ≤ y ≤ 1
I =
3.Medium
For f(x, y) = xy + 4x³, find the directional derivative Duf at (−1, 1) in the direction of v = (2, −1).
f(x, y) = xy + 4x³P = (−1, 1)v = (2, −1)
Duf =
4.Medium
For f(x, y) = 2x³y + x² + 3y² + 4xy, find the maximum rate of change of f at the point (1, 2), that is |∇f|.
f(x, y) = 2x³y + x² + 3y² + 4xyP = (1, 2)
|∇f| =
5.Hard
Find the critical points of f(x, y) = −x³ + 12x − y² − 4y, classify them, and give the value fmax of f at its local maximum.
f(x, y) = −x³ + 12x − y² − 4y
fmax =
6.Hard
Find the critical points of f(x, y) = x³ + y³ − 6xy, classify them, and give the value fmin of f at its local minimum.
f(x, y) = x³ + y³ − 6xy
fmin =
Answer key
- 1. fx(−1, 0.5) = −26.89
- 2. I = 60
- 3. Duf = 12.07
- 4. |∇f| = 28.43
- 5. fmax = 20
- 6. fmin = −8
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