Math Problem Statement

The query submitted by the user: double integral \( \int_0^2 \int_0^4 (6xy - 2y) \, dx \, dy \)

Solution

The expression in the image appears to be:

0204(6xy2y)dxdy\int_0^2 \int_0^4 (6xy - 2y) \, dx \, dy

This represents a double integral, where the region of integration is a rectangle with limits 0x40 \leq x \leq 4 and 0y20 \leq y \leq 2, and the function being integrated is 6xy2y6xy - 2y.

Let's solve this step by step.

Step 1: Integrate with respect to xx

The inner integral is:

04(6xy2y)dx\int_0^4 (6xy - 2y) \, dx

Treating yy as a constant, we can integrate term by term:

[ \int_0^4 6xy , dx = 6y \int_0^4 x , dx = 6y \left[\frac{x^2}{2}\right]_0^4 = 6y \left[\frac{16}{2}\right] = 48y ]

042ydx=2y041dx=2y[x]04=2y(40)=8y\int_0^4 -2y \, dx = -2y \int_0^4 1 \, dx = -2y [x]_0^4 = -2y(4 - 0) = -8y

So the result of the inner integral is:

48y8y=40y48y - 8y = 40y

Step 2: Integrate with respect to yy

Now, we integrate the result from the first step with respect to yy:

0240ydy=4002ydy=40[y22]02=40×42=80\int_0^2 40y \, dy = 40 \int_0^2 y \, dy = 40 \left[\frac{y^2}{2}\right]_0^2 = 40 \times \frac{4}{2} = 80

Final Result:

The value of the double integral is 8080.

Would you like more details on any part of this solution?


Here are five related questions:

  1. How do you determine the limits of integration in a double integral?
  2. What is the significance of changing the order of integration in double integrals?
  3. Can you evaluate a double integral over non-rectangular regions?
  4. What happens if the function within the integral is not separable?
  5. How would the result change if the integrand were 6xy22y6xy^2 - 2y?

Tip: Always check if the function inside the integral allows for simplifications or factorization, as it can make the computation easier.

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Math Problem Analysis

Mathematical Concepts

Calculus
Double Integration

Formulas

\( \int_a^b f(x) \, dx \) - Single Integral
\( \int_a^b \int_c^d f(x, y) \, dx \, dy \) - Double Integral

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

College Level