Page 77 - Calculus with Complex Numbers
P. 77
by observing that
An alternative way to sum this second series is to use cosec z. The singularities
of cosec z = 1/ sin z are at z = n:r where the residues are
1 1
Res cosec z = Res = = (- 1)/.
zccn,r zzcw,r sin c cos c C=/X
And cosec z is bounded on yx as in Section 7.3 since
cosec z d 9Nn' 9
2 z :% = --> 0
y n Z Nzn.z x;r
as N --> co. But
/-
