Question

Let f be the function given by f(x)=2x/sqr.(x^2+x+1)?
a.) In the viewing widow provided below, sketch the graph of f.
Viewing Window [-5,5] x [-3,3]
b.) Write an equation for each horizontal asymptote of the graph of f.
c.) Find the range of f. Use f'(x) to justify your answer
Note: f'(x)=(x+2)/(x^2+x+1)^(3/2)