# Help: could someone walk me through the maclaurin series of tan(z) [complex analysis]

1. May 20, 2007

### trickae

1. The problem statement, all variables and given/known data
By using an indirect method of dividing a taylor series to find the Maclaurin series of tan(z)

2. Relevant equations

z = x+iy
http://img142.imageshack.us/img142/9633/a1695fb96e78ca8dcb08788mi1.png [Broken]

3. The attempt at a solution

well I understand that we need to use the cauchy product:

cos (z) . tan(z) = sin(z)

we multiply a general case for coz z 's expansion x a polynomial series of sum(0,infinity) anZ^n

how do we end up with tan z = z + z^3/3 + 2z^5/15 + ....

Last edited by a moderator: May 2, 2017