\int_{\gamma}{fdz}=\int_{0}^{1}{ (\frac{1}{t^2+1}\cdot 0 - \frac{t}{t^2+1} \cdot 1})dt}+i \int_{0}^{1}{ (\frac{1}{t^2+1}\cdot 1 + \frac{t}{t^2+1} \cdot 0})dt} =