Math Core

Unit 4 · Test

Unit 4 test: Multiple Integrals

15 questions. Answer them all, then submit to see your score. Solutions unlock after you submit.

This test covers double integrals over rectangles and general regions, double integrals in polar coordinates, applications of double integrals, triple integrals, cylindrical and spherical coordinates, and change of variables with the Jacobian.

Question 1

Evaluate ∬R(x+2y) dA\displaystyle\iint_R (x + 2y)\,dA, where R=[0,2]×[0,1]R = [0, 2] \times [0, 1].

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 2

Evaluate ∫01∫02xy2 dy dx\displaystyle\int_0^1 \int_0^2 xy^2\,dy\,dx.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 3

Evaluate ∬Dxy dA\displaystyle\iint_D xy\,dA, where DD is the region between y=x2y = x^2 and y=xy = x for 0≤x≤10 \le x \le 1.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 4

Which integral equals ∫01∫x1f(x,y) dy dx\displaystyle\int_0^1 \int_x^1 f(x, y)\,dy\,dx with the order of integration reversed?

Question 5

Evaluate ∫01∫y1ex2 dx dy\displaystyle\int_0^1 \int_y^1 e^{x^2}\,dx\,dy by reversing the order of integration.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 6

Evaluate ∬D(x2+y2)dA\displaystyle\iint_D \left(x^2 + y^2\right)dA, where DD is the disk x2+y2≤9x^2 + y^2 \le 9.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 7

Evaluate ∬Dxy dA\displaystyle\iint_D xy\,dA, where DD is the part of the disk x2+y2≤4x^2 + y^2 \le 4 in the first quadrant.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 8

A lamina occupies the triangle x≥0x \ge 0, y≥0y \ge 0, x+y≤1x + y \le 1 and has density ρ(x,y)=x\rho(x, y) = x. Find its mass.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 9

Find the centroid (xˉ,yˉ)(\bar{x}, \bar{y}) of the upper half of the unit disk, x2+y2≤1x^2 + y^2 \le 1, y≥0y \ge 0.

Enter a point like (2, -3)

Question 10

Evaluate ∭Bxyz dV\displaystyle\iiint_B xyz\,dV, where B=[0,1]×[0,2]×[0,3]B = [0, 1] \times [0, 2] \times [0, 3].

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 11

Find the volume of the tetrahedron bounded by the coordinate planes and the plane x+2y+3z=6x + 2y + 3z = 6.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 12

Find the volume of the solid between the paraboloids z=x2+y2z = x^2 + y^2 and z=2−x2−y2z = 2 - x^2 - y^2.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 13

What is the volume element dVdV in spherical coordinates (ρ,θ,ϕ)(\rho, \theta, \phi)?

Question 14

Evaluate ∭Bx2+y2+z2 dV\displaystyle\iiint_B \sqrt{x^2 + y^2 + z^2}\,dV, where BB is the unit ball.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 15

Let RR be the rectangle bounded by x+y=0x + y = 0, x+y=2x + y = 2, x−y=0x - y = 0 and x−y=4x - y = 4. Use u=x+yu = x + y, v=x−yv = x - y to evaluate ∬R(x−y) dA\displaystyle\iint_R (x - y)\,dA.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.