Evaluate I = ∫12 ∫12 (−3xy² − 1) dy dx over the rectangle 1 ≤ x ≤ 2, 1 ≤ y ≤ 2.
Multivariable calculus worksheet with answers
1.Easy
f = −3xy² − 11 ≤ x ≤ 21 ≤ y ≤ 2
I =
2.Easy
For f(x, y) = −2x³y − x³ + 3y³, find the partial derivative ∂f/∂y at the point (3, −1).
f(x, y) = −2x³y − x³ + 3y³P = (3, −1)
fy(3, −1) =
3.Medium
z = 3x²y³ − x² + 3y³ with x = −3t + 2 and y = −t². Use the chain rule to find dz/dt at t = −1.
z = 3x²y³ − x² + 3y³x = −3t + 2y = −t²t = −1
dz/dt =
4.Medium
For f(x, y) = −3x²y² + x² − 5y² − 3xy, find the direction of steepest ascent at (−2, 3) as the angle θ from the positive x-axis, in degrees between −180° and 180°.
f(x, y) = −3x²y² + x² − 5y² − 3xyP = (−2, 3)
θ = °
5.Hard
f(x, y) = x³ − 3x + y² + 4y has a critical point at (−1, −2). Compute the discriminant D = fxxfyy − fxy² there.
f(x, y) = x³ − 3x + y² + 4yP = (−1, −2)
D =
6.Hard
Use polar coordinates to evaluate I = ∬R (x² + y²) dA, where R is the disc x² + y² ≤ 1.
f = x² + y²0 ≤ r ≤ 10 ≤ θ ≤ 2π
I =
Answer key
- 1. I = −11.5
- 2. fy(3, −1) = −45
- 3. dz/dt = 588
- 4. θ = −45.3 °
- 5. D = −12
- 6. I = 1.571
Full step-by-step solutions: practise this topic on examproblems.com.