Bereken:
$\eqalign{
& a.\,\,\,\int {\frac{{{e^{\frac{1}{x}}}}}{{{x^2}}}} \,dx \cr
& b.\,\,\,\int {\frac{1}{{x\left( {1 + {{\ln }^2}x} \right)}}\,dx} \cr
& c.\,\,\,\int {\frac{1}{{x \cdot \ln \left( {\sqrt x } \right)}}} \,dx \cr
& d.\,\,\,\int {\frac{{\sqrt x }}{{1 + \sqrt x }}} \,dx \cr} $