English: So, diagonal elements that your $\frac{\partial Q_{i}}{\partial V_{i}} = - 2\left| V_{i} \right|\left| Y_{ii} \right|\sin\sin\ \theta_{ii}\ - \left| V_{i} \right|\left| V_{k} \right|\left| Y_{ik} \right|\sin\sin\ \left( \theta_{ik} - \delta_{i} + \delta_{k} \right)\ $.
Telugu: కాబట్టి, మీ $\frac{\పాక్షిక Q_{i}}{\పాక్షిక V_{i}} = - 2\ఎడమ| V_{i} \కుడి|\ఎడమ| Y_{ii} \కుడి|\పాపం\పాపం\ \theta_{ii}\ - \ఎడమ| V_{i} \కుడి|\ఎడమ| V_{k} \కుడి|\ఎడమ| Y_{ik} \కుడి|\sin\sin\ \ఎడమ( \theta_{ik} - \delta_{i} + \delta_{k} \కుడి)\ $.