This research paper examines the equivalence between mass and energy in special relativity by utilizing mathematical methods, including the de Broglie equation, to establish relationships between momentum, energy, mass, and the speed of light. It emphasizes the role of tensors and multidimensional spaces in the mathematical foundation of relativity and discusses various theoretical backgrounds such as coordinate transformations and tensor operations. The paper ultimately aims to connect energy and momentum through mathematical relationships and explore the implications for understanding mass-energy equivalence.