Which of the following statements is/are correct?
1
If f(z) = tan z is complex function then \(\mathop \smallint \nolimits_C f\left( z \right)dz = - 2\pi i\), where C is a closed curve.
2
If f(z) = tan z is a complex function then \(\mathop \smallint \nolimits_C f\left( z \right)dz = 0\), where C is a closed curve.
3
If \(I = \mathop \smallint \nolimits_C f\left( z \right)dz\), where f(z) is a complex function which is analytic at all points except at some finite number of singular points within and on a closed curve C, then \(\ln \left( {\frac{I}{{2\pi R}}} \right) = \frac{{i\pi }}{2}\), where R is the residue of f(z).
4
The value of \(\mathop \smallint \nolimits_{z = 0}^{1 + i} z\;dz\) along the curve y = x4 is i, where z = x + iy.