Solution D19 by the Lagrangian method B18 by Yablonsky

Task D19 B18 by the Lagrange method of the 2nd kind. "Application of the general equation of dynamics to the study of the motion of a mechanical system with one degree of freedom (the Lagrange method of the second kind)"

! This solution is the second way to solving D19. Therefore, a solution without a picture!
After payment you will receive a rar-archive containing black-and-white drawings in tiff format (resolution 200-300 dpi) with the decision of course work from the collection edited by A.A. Yablonsky 1985-2006 edition.
The work was done in an understandable, legible handwriting by the teacher with 18 years of experience and tested for 11 years in one of the universities and more than two years on the Internet.