꿈라CBT전계 \(E\)의 \(x\), \(y\), \(z\) 성분을 각각 \(E_x\), \(E_y\), \(E_z\)라 할 때 \(\mathrm{div}\,E\)는?
- 1\(\dfrac{\partial E_x}{\partial x}+\dfrac{\partial E_y}{\partial y}+\dfrac{\partial E_z}{\partial z}\)
- 2\(i\dfrac{\partial E_x}{\partial x}+j\dfrac{\partial E_y}{\partial y}+k\dfrac{\partial E_z}{\partial z}\)
- 3\(\dfrac{\partial^{2} E_x}{\partial x^{2}}+\dfrac{\partial^{2} E_y}{\partial y^{2}}+\dfrac{\partial^{2} E_z}{\partial z^{2}}\)
- 4\(i\dfrac{\partial^{2} E_x}{\partial x^{2}}+j\dfrac{\partial^{2} E_y}{\partial y^{2}}+k\dfrac{\partial^{2} E_z}{\partial z^{2}}\)