For f(x, y) = 4x²y³ − 4x³ + 4y² + 4xy, find the second partial derivative ∂²f/∂y² at (−2, 2).
Multivariable calculus worksheet with answers
1.Easy
f(x, y) = 4x²y³ − 4x³ + 4y² + 4xyP = (−2, 2)
fyy(−2, 2) =
2.Easy
For f(x, y) = x²ey, find the mixed second partial derivative ∂²f/∂x∂y at (−1, 1).
f(x, y) = x²eyP = (−1, 1)
fxy(−1, 1) =
3.Medium
For f(x, y) = 3x²e−y, find the maximum rate of change of f at the point (2, −1), that is |∇f|.
f(x, y) = 3x²e−yP = (2, −1)
|∇f| =
4.Medium
For f(x, y) = 4x³y + 5x² − y² + 3xy, find the directional derivative Duf at P(1, −1) in the direction towards Q(5, 2).
f(x, y) = 4x³y + 5x² − y² + 3xyP = (1, −1)Q = (5, 2)
Duf =
5.Hard
Find the area I = ∬R 1 dA of the region R between the parabola y = x² and the line y = x.
y = x²y = xf = 1
I =
6.Hard
Use polar coordinates to evaluate I = ∬R √(x² + y²) dA, where R is the disc x² + y² ≤ 9.
f = √(x² + y²)0 ≤ r ≤ 30 ≤ θ ≤ 2π
I =
Answer key
- 1. fyy(−2, 2) = 200
- 2. fxy(−1, 1) = −5.437
- 3. |∇f| = 46.13
- 4. Duf = 1.4
- 5. I = 0.1667
- 6. I = 56.55
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