Finding derivative using FFT

I have an array of the following form:

1	-1.77000000000000e-15 - 0.726930931000000i
2	-0.211027375000000    + 1.20000000000000e-15i
3	-1.03000000000000e-15 - 0.0619000000000000i
4	-0.0297000000000000   - 2.84000000000000e-16i
5	-6.04000000000000e-16 - 0.0350000000000000i
6	-0.00560000000000000  - 2.56000000000000e-15i
7	 3.64000000000000e-15 - 0.0202000000000000i
8	 0.00351000000000000  - 1.03000000000000e-16i
9	 8.05000000000000e-16 - 0.0116000000000000i
10	 0.00748000000000000  - 2.65000000000000e-16i
11	-4.54000000000000e-15 - 0.00540000000000000i
12	 0.00904000000000000  - 3.32000000000000e-15i
13	 1.07000000000000e-17 - 9.72000000000000e-15i
14	 0.00904000000000000  + 6.18000000000000e-15i
15	-6.43000000000000e-15 + 0.00540000000000000i
16	 0.00748000000000000  - 6.13000000000000e-16i
17	-1.42000000000000e-15 + 0.0116000000000000i
18	 0.00351000000000000  + 7.64000000000000e-15i
19	-2.66000000000000e-15 + 0.0202000000000000i
20	-0.00560000000000000  + 3.10000000000000e-16i
21	-6.90000000000000e-15 + 0.0350000000000000i
22	-0.0297000000000000   + 1.09000000000000e-14i
23	 5.54000000000000e-15 + 0.0619000000000000i
24	-0.211027375000000    + 2.30000000000000e-14i
25	 1.18000000000000e-13 + 0.726930931000000i
26	 1.00000000000000     - 1.19000000000000e-13i

where first column is x and second column is . And is a periodic function

How can I find it's first and second derivative using FFT?