I have written the function V(R) in Maple like this:

"V(R) := D_e * (1 - exp(-a * (R - R_e)))^2"

Where D_e, a and R_e are constants but Maple evaluates them as variables. Then before the function I have now written:

"Parameters(D_e, a, R_e)" and even "constants := D_e, a, R_e" (if that helps)

I would like to find the limit as R approaches infinity, but Maple just substitutes R with ∞ in the function. The answer should just be D_e, and not "D_e * (1 - exp(-a * (∞ - R_e)))^2"

Thanks for any help out there :)