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$\nabla \times \nabla \times \mathrm{P}$, where $\mathrm{P}$ is a vector, is equal to

1. $\mathrm{P} \times \nabla \times \mathrm{P}-\nabla^{2} \mathrm{P}$
2. $\nabla^{2} \text{P} +\nabla(\nabla \cdot \text{P})$
3. $\nabla^{2} \mathrm{P}+\nabla \times \mathrm{P}$
4. $\nabla(\nabla \cdot \mathrm{P})-\nabla^{2} \mathrm{P}$