Question

Points of inflection for y=tan^-1(x)

Answer 1

\[dy/dx=1/(1+x^2)\]
This can never equal zero because x^2 can never be less than 0.
\[d^2y/dx^2=2x/(1+x^2)^2\]. This equals zero when x=0. so there is a point of inflection at x=0.