Hamilton's principle and Lagrange's equation
Pages 229-231 Classical dynamics of particles and systems by S. T. Thorntom and J. B. Marion, 5th. Edition Harcourt Brace and company (2012).
Pages 229-231 Classical dynamics of particles and systems by S. T. Thorntom and J. B. Marion, 5th. Edition Harcourt Brace and company (2012).