Update README.md

Signed-off-by: Fabiana Campanari <fabicampanari@gmail.com>

README.md

@@ -147,6 +147,7 @@ In this case, we can use L'Hôpital's rule, as the limit is of the form \(\frac{
 \[
 \begin{align*}
 \lim_{{x \to \infty}} \frac{{x^2}}{{2x^2 - x}} &= \lim_{{x \to \infty}} \frac{{\frac{d}{dx}[x^2]}}{{\frac{d}{dx}[2x^2 - x]}} \\
+&= \lim_{{x \to \infty}} \frac{{2x}}{{4x - 1}} \\