Title Numerical Calculation of Fractional Derivatives for the Sinc Functions via Legendre Polynomials Type of Research Article Keywords Sinc functions, Fractional derivatives, Collocation method, Caputo derivative Shifted Legendre polynomials Abstract This paper provides the fractional derivatives of the Caputo type for the sinc functions. It allows to use efficient numerical method for solving fractional differential equations. At first, some properties of the sinc functions and Legendre polynomials required for our subsequent development are given. Then we use the Legendre polynomials to approximate the fractional derivatives of sinc functions. Some numerical examples are introduced to demonstrate the reliability and effectiveness of the introduced method. Researchers (First Researcher)، Ali Khani (Second Researcher)، mohammad reza azizi (Third Researcher)