Determine all intervals over which the function f(x)=∫√(1+t^2) dt is concave upward
I know concave up means the f"(x)>0, so you have to get the second derivative
The Attempt at a Solution
f'(x)=√(1+x^) by susbituting in x
This is equal to:
Then, I'm really confused on what to do next because the denominator is never zero, so would the only critical point be 0 and you check to the left and right of that?