@Carl Love 

@Carl Love 

@Carl Love 

@Carl Love I will wait for the Maple solution. Thanks

@glcrawfo 

@Carl Love this is what I got.

@Carl Love yes that's correct.

This is the beginning of the solution where I'm stuck. Does this help??

restart;
step := t -> piecewise(t < 0, 0, 1);
f := t -> sum(-1 and n*step(t - n), n = 0 .. 50);
 step := proc (t) options operator, arrow; piecewise(t < 0, 0, 

    1) end proc
f := proc (t) options operator, arrow; sum(-1 and n*step(t-n), 

   n = 0 .. 50) end proc
R = 20, C = 0.01, L = 10;
                    R = 20, C = 0.01, L = 10

LC*d^2*x*1/(d^2*t) + RC*dx/dt + x(t)/C = (200*x(t))/3;
                 LC x   RC dx   x(t)   200     
                 ---- + ----- + ---- = --- x(t)
                  t      dt      C      3      
 

@Carl Love can you show me how to plot x(t) over 0 <= t <= 5, or any other interval. Thanks

@Christian Wolinski can you help me with the Maple solution?