Question 6 section 8.1 of Introduction to real analysis by Bartle and Sherbert.
Show that $lim(Arctan nx) = (pi/2)sgn x$ for $x$ in R, $x>=0$.
I have a final coming up and I've started doing some of the exercises in the book. I'm not sure how to go about proving this. I know I'm trying to show |Arctan(nx)-$(pi/2)sgn| < \epsilon$ but the sgn function is throwing me off. Any help is appreciated.