Problem

Part I Multiple Choice

3. Consider the function $f(x)=\dfrac{1+e^{-x^2}}{1-e^{-x^2}}$.

(A) $f(x)$ does not have any horizontal asymptotes and any vertical asymptotes.

(B) $f(x)$ has a horizontal asymptote, but $f(x)$ does not have any vertical asymptotes.

(C) $f(x)$ has a vertical asymptote, but $f(x)$ does not have any horizontal asymptotes.

(D) $f(x)$ has a horizontal asymptote and a vertical asymptote.