Math Problem Statement

Evaluate the triple integral \( \iiint_E \frac{e^{-2x} \sin^2(z)}{\sqrt{y}} \, dV \) where \( E = [0,1] \times [1,2] \times [0,\pi] \).

Solution

To evaluate the triple integral given in the image:

Ee2xsin2(z)ydV\iiint_E \frac{e^{-2x} \sin^2(z)}{\sqrt{y}} \, dV

where E=[0,1]×[1,2]×[0,π]E = [0, 1] \times [1, 2] \times [0, \pi], we proceed by setting up the bounds for each variable based on the region EE.

Step-by-Step Solution

  1. Identify Integration Bounds:

    • For xx, 0x10 \leq x \leq 1.
    • For yy, 1y21 \leq y \leq 2.
    • For zz, 0zπ0 \leq z \leq \pi.
  2. Set Up the Integral: The integral can be written as: 01120πe2xsin2(z)ydzdydx.\int_0^1 \int_1^2 \int_0^{\pi} \frac{e^{-2x} \sin^2(z)}{\sqrt{y}} \, dz \, dy \, dx.

  3. Evaluate the Integral Over zz: Since sin2(z)\sin^2(z) only depends on zz, we can integrate with respect to zz first: 0πsin2(z)dz=0π1cos(2z)2dz.\int_0^{\pi} \sin^2(z) \, dz = \int_0^{\pi} \frac{1 - \cos(2z)}{2} \, dz. Using the identity sin2(z)=1cos(2z)2\sin^2(z) = \frac{1 - \cos(2z)}{2}, we can simplify this as: =120π(1cos(2z))dz=12[zsin(2z)2]0π.= \frac{1}{2} \int_0^{\pi} (1 - \cos(2z)) \, dz = \frac{1}{2} \left[ z - \frac{\sin(2z)}{2} \right]_0^{\pi}. Evaluating this, we get: =12(π0)=π2.= \frac{1}{2} \left( \pi - 0 \right) = \frac{\pi}{2}.

  4. Evaluate the Integral Over yy: Now, integrate with respect to yy: 121ydy.\int_1^2 \frac{1}{\sqrt{y}} \, dy. This integral evaluates as follows: =[2y]12=2(21).= \left[ 2 \sqrt{y} \right]_1^2 = 2(\sqrt{2} - 1).

  5. Evaluate the Integral Over xx: Finally, integrate with respect to xx: 01e2xdx.\int_0^1 e^{-2x} \, dx. This evaluates to: =[e2x2]01=12(1e2).= \left[ -\frac{e^{-2x}}{2} \right]_0^1 = \frac{1}{2} (1 - e^{-2}).

  6. Combine Results: Now, multiply all results together: π22(21)12(1e2).\frac{\pi}{2} \cdot 2(\sqrt{2} - 1) \cdot \frac{1}{2} (1 - e^{-2}). Simplifying, we get: =π(21)(1e2)2.= \frac{\pi (\sqrt{2} - 1)(1 - e^{-2})}{2}.

Final Answer:

Ee2xsin2(z)ydV=π(21)(1e2)2.\iiint_E \frac{e^{-2x} \sin^2(z)}{\sqrt{y}} \, dV = \frac{\pi (\sqrt{2} - 1)(1 - e^{-2})}{2}.

Would you like more details on any specific step?

Here are some related questions you might find useful:

  1. How can we use trigonometric identities to simplify integrals involving sine and cosine?
  2. What are some techniques for evaluating integrals over rectangular regions?
  3. How do exponential functions affect the convergence of integrals?
  4. What is the significance of evaluating integrals in different orders of integration?
  5. How do we handle integrals that involve square root functions?

Tip: For triple integrals, always set up the bounds for each variable carefully to ensure the correct order of integration.

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Math Problem Analysis

Mathematical Concepts

Triple Integration
Exponential Functions
Trigonometric Identities
Integration Techniques

Formulas

\( \sin^2(z) = \frac{1 - \cos(2z)}{2} \)
Integration of exponential functions \( \int e^{ax} \, dx \)
Square root and fractional integration

Theorems

Fundamental Theorem of Calculus
Integration by Parts

Suitable Grade Level

Undergraduate (Calculus III or Multivariable Calculus)