Question 911921
Graphing the function {{{f(x)=(8x)/(x^2+1)}}} gives you


{{{drawing(500,500,-10,10,-10,10,
  grid(1),
  graph(500,500,-10,10,-10,10,0,(8x)/(x^2+1))
)}}}


So we see that the graph decreases on the interval *[Tex \Large (-\infty,-1)\cup(1,\infty)] and increases on the interval *[Tex \Large (-1,1)]