Delta denotes the Laplace operator defined by
$$\Delta \varphi=\frac{\partial^{2} \varphi}{\partial x^{2}}+\frac{\partial^{2} \varphi}{\partial y^{2}}+\frac{\partial^{2} \varphi}{\partial z^{2}}$$
Prove the identity
$$\operatorname{curl}(\operatorname{curl}(\mathbf{F}))=\nabla(\operatorname{div}(\mathbf{F}))-\Delta \mathbf{F}$$
where $\Delta \mathbf{F}$ denotes $\left\langle\Delta F_{1}, \Delta F_{2}, \Delta F_{3}\right\rangle.$