I need the second derivative of f(x)= (x+1)/ sqrt[(x^2) +1]
I got f'(x)= (1-x) / [(x^2) +1]^(3/2)
Solution for f''(x)=[(2x^2) - 3x -1] / [(x^2) +1]^(5/2)
I tried the Quotient Rule but I do not get the solution...
Can someone explain how to get to the solution?