Hello,

I'm trying to input a time series model into R, but I keep getting this error: Error: could not find function "X" when I try to run

x(t) <- .5*x_(t-1)+E_(t)-.5*E_(t-1)

Or sometimes I get the Unexpected Input error if I try to do the parentheses in a different way.

I've had to input a time series model before and it worked fine, but it's not wanting to this time.

If anyone can help, I would really appreciate it.