Mixed Berndt-type integrals and generalized Barnes multiple zeta functions

In this paper, we define and study four families of Berndt-type integrals, called mixed Berndt-type integrals, whose integrands contain (hyperbolic) sine and cosine functions. Using contour integration, these integrals are first converted to hyperbolic (infinite) sums of Ramanujan type, all of which can be calculated in closed form by comparing both the Fourier and the Maclaurin series expansions of certain Jacobi elliptic functions. These sums can be expressed as rational polynomials in Γ ( 1 / 4 ) and π − 1 which give rise to the closed formulas of the mixed Berndt-type integrals we are interested in. Moreover, we also present some interesting consequences and illustrative examples. Additionally, we define a generalized Barnes multiple zeta function, and obtain an integral representation of it. Furthermore, we give an alternative evaluation of the mixed Berndt-type integrals in terms of the generalized Barnes multiple zeta function. Finally, we obtain some direct evaluations of rational linear combinations of the generalized Barnes multiple zeta function.