Test

<latex>{\underline Y = \frac{1}{ {\underline Z } } = \frac{1}{ {\left| {\underline Z } \right|{\mathrm {e} } ^{ {\mathrm{j} }\phi } } } = \frac{ {I_{\mathrm{m} } } }{ {U_{\mathrm{m} } } }{\mathrm {e} } ^{ - {\mathrm{j} }\phi } = \left| {\underline Y } \right|{\mathrm {e} } ^{ - {\mathrm{j} }\phi } = \left| {\underline Y } \right|\left( {\cos \phi - {\mathrm{j} }\sin \phi } \right).}</latex>