f(x) = (1+2x)/(2+x^2) Question: Compute the second derivative and use it to find the region where f(x) is concave and where is convex.
f''(x) = (4x^3 + 6x^2 - 24x - 4)/(x^2 + 2)^3 I cant find x to f''(x) = 0 so I cant find the region where f(x) is concave or convex.
Can anyone help me please?

I get a different result for f''(x), where the numerator is 2nd order. What do you have for f'(x)? Hint: don't forget to divide both numerator and denominator of f'(x) by any common factors.