cos(4) cos(6) cos(8) cos(10) cos(12) cos(14) cos(16) cos(18) cos(20)
------ + ------ + ------ + ------- + ------- + -------- + ---------- + ------------ + -------------- + cos(2)
4 36 576 14400 518400 25401600 1625702400 131681894400 13168189440000
$$\cos{\left(2 \right)} + \frac{\cos{\left(4 \right)}}{4} + \frac{\cos{\left(8 \right)}}{576} + \frac{\cos{\left(10 \right)}}{14400} + \frac{\cos{\left(16 \right)}}{1625702400} + \frac{\cos{\left(20 \right)}}{13168189440000} + \frac{\cos{\left(18 \right)}}{131681894400} + \frac{\cos{\left(14 \right)}}{25401600} + \frac{\cos{\left(12 \right)}}{518400} + \frac{\cos{\left(6 \right)}}{36}$$
cos(4)/4 + cos(6)/36 + cos(8)/576 + cos(10)/14400 + cos(12)/518400 + cos(14)/25401600 + cos(16)/1625702400 + cos(18)/131681894400 + cos(20)/13168189440000 + cos(2)