Find the derivative of f(x)=xarctan(x)−12ln(1+x2)f(x) = x \arctan(x) - \frac{1}{2} \ln(1+x^2)f(x)=xarctan(x)−21ln(1+x2).
arctan(x)\arctan(x)arctan(x)
xarctan(x)x \arctan(x)xarctan(x)
11+x2\frac{1}{1+x^2}1+x21
111