Number 12.23. Please help me

12.23. A ladder of mass M and length L rests against a smooth wall and makes an angle 0 with the floor. The ladder starts sliding both on the floor and the wall. Set up Lagrange's equations of motion, as- suming the ladder remains in contact with the wall. At what angle will the ladder leave the wall? 12.24. A mass m is suspended by a string of length I from a support S and oscillates as a pendulum in a vertical plane containing the X-axis and making an angle 0 with the vertical, as shown in