The value of is `sum_(k=1)^(10)(sin"" (2k pi)/(11)+ icos ""(2k pi)/(11))` is

Find the value of sum_(k =1)^(8)(cos"" (2k pi)/(9) + i(sin""2k pi)/(9))

The value of sum_(r=1)^(11)tan^(2)((r pi)/(24)) is

The value of sum_(k=1)^(13) (1)/(sin((pi)/(4) + ((k-1)pi)/(6)) sin ((pi)/(4)+ (kpi)/(6))) is equal to

Find the value of ((1 + sin"" (pi)/(10) + i cos"" (pi)/(10))/(1 + sin"" (pi)/(10) - i cos"" (pi)/(10)))^(10) .

Evaluate sum_(k-1)^11(2+3^k)

The value of cos""(pi)/(11)+cos""(3pi)/(11)+cos""(5pi)/(11)+cos""(7pi)/(11)+cos""(9pi)/(11), is

Find sum_(k=1)^(n)(1)/(k(k+1)) .