Use the divergence theorem to find the inward flux of the vector field F = 3x²y²1+ yj - 6xy² zk through the boundary of the solid bounded by the paraboloid z = x² + y² and the plane z = 2y. Hint: Use cylindrical coordinates, and note that cos20 = (1 + cos20)/2, sin²0 = (1-cos20)/2

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Chapter2: Second-order Linear Odes
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### Problem Q9

**Objective:**
Use the divergence theorem to find the inward flux of the vector field 

\[ \mathbf{F} = 3x^2y^2\mathbf{i} + y\mathbf{j} - 6xy^2z\mathbf{k} \]

through the boundary of the solid bounded by the paraboloid 

\[ z = x^2 + y^2 \]

and the plane 

\[ z = 2y. \]

**Hint:** 
Use cylindrical coordinates, and note that 

\[ \cos^2\theta = \frac{1 + \cos 2\theta}{2}, \]
\[ \sin^2 \theta = \frac{1 - \cos 2\theta}{2}. \]

**Solution Approach:**
1. **Divergence Theorem Setup:**
   - The divergence theorem relates the flux of a vector field through a closed surface to the volume integral of the divergence of the vector field over the region enclosed by the surface. 
   
   \[ \iint_{\partial V} \mathbf{F} \cdot \mathbf{n} \, dS = \iiint_V (\nabla \cdot \mathbf{F}) \, dV. \]

2. **Compute the Divergence \( \nabla \cdot \mathbf{F} \):**
   - Calculate the partial derivatives:

   \[ \nabla \cdot \mathbf{F} = \frac{\partial}{\partial x}(3x^2y^2) + \frac{\partial}{\partial y}(y) + \frac{\partial}{\partial z}(-6xy^2z). \]

3. **Region Description in Cylindrical Coordinates:**
   - Convert the given surfaces to cylindrical coordinates where:
     
     \[ x = r\cos \theta, \, y = r\sin \theta, \, z = z. \]
     
     The paraboloid \( z = x^2 + y^2 \) becomes \( z = r^2 \), and the plane \( z = 2y \) becomes \( z = 2r\sin \theta \).
     
4. **Volume Integral Setup:**
   - Boundaries for the integral in cylindrical coordinates:
  
     - Radial coordinate \( r \) ranges from 0 to the value where \( z \
Transcribed Image Text:### Problem Q9 **Objective:** Use the divergence theorem to find the inward flux of the vector field \[ \mathbf{F} = 3x^2y^2\mathbf{i} + y\mathbf{j} - 6xy^2z\mathbf{k} \] through the boundary of the solid bounded by the paraboloid \[ z = x^2 + y^2 \] and the plane \[ z = 2y. \] **Hint:** Use cylindrical coordinates, and note that \[ \cos^2\theta = \frac{1 + \cos 2\theta}{2}, \] \[ \sin^2 \theta = \frac{1 - \cos 2\theta}{2}. \] **Solution Approach:** 1. **Divergence Theorem Setup:** - The divergence theorem relates the flux of a vector field through a closed surface to the volume integral of the divergence of the vector field over the region enclosed by the surface. \[ \iint_{\partial V} \mathbf{F} \cdot \mathbf{n} \, dS = \iiint_V (\nabla \cdot \mathbf{F}) \, dV. \] 2. **Compute the Divergence \( \nabla \cdot \mathbf{F} \):** - Calculate the partial derivatives: \[ \nabla \cdot \mathbf{F} = \frac{\partial}{\partial x}(3x^2y^2) + \frac{\partial}{\partial y}(y) + \frac{\partial}{\partial z}(-6xy^2z). \] 3. **Region Description in Cylindrical Coordinates:** - Convert the given surfaces to cylindrical coordinates where: \[ x = r\cos \theta, \, y = r\sin \theta, \, z = z. \] The paraboloid \( z = x^2 + y^2 \) becomes \( z = r^2 \), and the plane \( z = 2y \) becomes \( z = 2r\sin \theta \). 4. **Volume Integral Setup:** - Boundaries for the integral in cylindrical coordinates: - Radial coordinate \( r \) ranges from 0 to the value where \( z \
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