Matlab are welcome! Manual solution process are neccessary

Homework:

$($Newton $2$nd Law$)$ The building frame structure in Fig. Prob$-1$ consists of a rigid horizontal member BC of mass $m$ supported by two vertical columns each of whose bending stiffness is El$.$ Neglect the effect of the weight of BC on the stiffness of the vertical members.

$($a$)$ Determine the equation of motion of mass $m.$

$($b$)$ How would the equation of motion differ if the left$-$hand column had a stiffness $2EI$ with no other changes to the structure?