pkg load symbolic
syms A funcz funcf z f
A(z) = poly2sym({1/2 1}, z)
vpasolve(A(z)==0,z)
funcz(z) = 1/((A(z)*A(1/z)))
funcf(f) = funcz(exp(sym(1i)*f))
int(funcf, f, [sym(0) 2*sym(pi)])
