Question

what is signum function

Answer 1

signum function,
      the important concept of calculus.its actual meaning is
 $y = \frac{|x|}{x}$
i.e y = 1 when x >0
       = -1 when x<0
       = 0 when x = 0


see the graph.
       

Answer 2

$\textbf{Answer is in Attachment !}$