Find all zeros and periods of cosh and sinh z. Solution We have that coshz = cos (iz), thus the zeros of cosh z are at z = in/2+im, m=0,1, +2,..., and the periods of cosh z are 2ami, m = 0.1.2..... We have that sinh = -isin (iz), thus the zeros of sinh z are at z = m^i, m 0,1, 2..... ..... and the periods of cosh z are 2xmi, m = 0, 1, 2,....