1.求下列函数的导数.(1)f(x)=12x2−x−1xf(x)=\frac{1}{2}{x^2}-x-\frac{1}{x}f(x)=21x2−x−x1;(2)f(x)=ex+lnx+sinxf(x)=e^{x}+lnx+\sin xf(x)=ex+lnx+sinx.