f(x)=√(1+lnx²)f'(x)=[1/2√(1+lnx²)]·[2x/x²] =1/[x√(1+lnx²)]f(x)=√(1+ln²x)f'(x)=[1/2√(1+ln²x)]·[2lnx/x] =lnx/[x√(1+lnx²)]
