y=(1+x²)arctanxy ′ = 2x arctanx + (1+x²)/(1+x²) = 2x arctanxy ′′ = 2arctanx + 2x/(1+x²)y=xe^xy ′ = e^x+xe^x = (1+x)e^xy ′′ = e^x+(1+x)e^x = (2+x)e^xy(n) = (n+x)e^x
