Question

what's the derivative of f(x) = 5x/(1+x^2)

Answer 1

f(x) = 5x/(1+x^2)
f' (x) = 5 [ (1+x^2) - 2x^2] / (1+x^2)^2
= 5 [ 1 - x^2 ] / (1+x^2)^2

Answer 2

so like how did you get that