Evaluate I = ∫13 ∫13 (6x²y² + 5) dy dx over the rectangle 1 ≤ x ≤ 3, 1 ≤ y ≤ 3.
Multivariable calculus worksheet with answers
1.Easy
f = 6x²y² + 51 ≤ x ≤ 31 ≤ y ≤ 3
I =
2.Easy
For f(x, y) = 3y·e−xy, find the mixed second partial derivative ∂²f/∂x∂y at (0.5, 1).
f(x, y) = 3y·e−xyP = (0.5, 1)
fxy(0.5, 1) =
3.Medium
The tangent plane to z = −3xy³ − 2x² + 3y² − 3xy at the point where (x, y) = (1, 3) can be written as z = px + qy + c. Find c.
f(x, y) = −3xy³ − 2x² + 3y² − 3xy(a, b) = (1, 3)
c =
4.Medium
For f(x, y) = 5xy + x² − y², find the maximum rate of change of f at the point (1, 1), that is |∇f|.
f(x, y) = 5xy + x² − y²P = (1, 1)
|∇f| =
5.Hard
Evaluate I = ∬T (2x − y) dA over the triangle T bounded by y = 0, x = 4 and y = 2x.
f = 2x − y0 ≤ x ≤ 40 ≤ y ≤ 2x
I =
6.Hard
The marked points are the critical points of f(x, y) = −x³ + 3x − y². Click the saddle point.
f(x, y) = −x³ + 3x − y²
- 1A (1, 0)
- 2B (−1, 0)
Answer key
- 1. I = 470.7
- 2. fxy(0.5, 1) = −2.729
- 3. c = 227
- 4. |∇f| = 7.616
- 5. I = 42.67
- 6. B (−1, 0)
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