Hi, I was given the following question, and I am not entirely sure how to approach it.
Find the constant a such that
lim x->infinity ((x+a)/(x-a))^x=e
I have tried applying l'hopitals rule, and substituting x=1/y so that the limit becomes
lim y->0 ((1+ay)/1-ay))
However, I keep getting stuck. Guidance would be much appreciated.
Thank you very much!