Question: User: (a) (i) State the Divergence theorem without proof.
1. **Problem Statement:** State the Divergence theorem without proof.
2. **Divergence Theorem Formula:**
The Divergence theorem relates the flux of a vector field through a closed surface to the divergence of the field inside the volume bounded by the surface.
It is stated as:
$$\iint_{S} \mathbf{F} \cdot \mathbf{n} \, dS = \iiint_{V} (\nabla \cdot \mathbf{F}) \, dV$$
where:
- $S$ is a closed surface bounding the volume $V$.
- $\mathbf{F}$ is a vector field.
- $\mathbf{n}$ is the outward unit normal vector on $S$.
- $\nabla \cdot \mathbf{F}$ is the divergence of $\mathbf{F}$.
3. **Explanation:**
The theorem states that the total outward flux of the vector field $\mathbf{F}$ across the closed surface $S$ is equal to the integral of the divergence of $\mathbf{F}$ over the volume $V$ enclosed by $S$.
This theorem is fundamental in vector calculus and is used to convert surface integrals into volume integrals and vice versa.