A_N = TAN^2((π *N)/(4* (N + 2)))
3		cot^2((π)/12)≈13.92820323027550	tan^2((π)/12)≈0.071796769724490742
4		cot^2(π/8)≈5.8284271247461		
5		cot^2((3 π)/20)≈3.851839996319182	
6		cot^2((π)/6)=3 
7		cot^2((5 π)/28)≈2.532843230615688
8		cot^2((3 π)/16)≈2.239828808843550
9		cot^2((7 π)/36)≈2.03960672916147
10		cot^2((π)/5)≈1.89442719099991
11		cot^2((9 π)/44)≈1.78447814814636
12		cot^2((5 π)/24)≈1.6983963724170
13		cot^2((11 π)/52)≈1.629211495628917
14		cot^2((3 π)/14)≈1.572416528431
15		cot^2((13 π)/60)≈1.524970987218355
16		cot^2((7 π)/32)≈1.4847508418703
17		cot^2((15 π)/68)≈1.450228261611679
18		cot^2((2 π)/9)≈1.420276625461
19		cot^2((17 π)/76)≈1.3940472215425
20		cot^2((9 π)/40)≈1.370888706465
21		cot^2((19 π)/84)≈1.350292994004402
22		cot^2((5 π)/22)≈1.33185799317496
23		cot^2((21 π)/92)≈1.3152613845107677
24		cot^2((11 π)/48)≈1.300241803840
25		cot^2((23 π)/100)≈1.28658510503
26		cot^2((3 π)/13)≈1.27411417292
27		cot^2((25 π)/108)≈1.2626812613688
28		cot^2((13 π)/56)≈1.25216215588
29		cot^2((27 π)/116)≈1.24245167383
30		cot^2((7 π)/30)≈1.23346015809
31		cot^2((29 π)/124)≈1.225110717528
32		cot^2((15 π)/64)≈1.21733703535