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

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

The value of lim_(n rarroo) sum_(r=1)^(n)(1)/(sin{((n+r)pi)/(4n)}).(pi)/(n) is equal to

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

The value of sum_(k=1)^(10)((sin(2 pi k))/(11)-i(cos(2 pi k))/(11)) is

The value of sum_(k=1)^(13)tan((k pi)/(12))tan(((k-1)pi)/(12)) is

sin^(-1)(cos((5pi)/4)) is equal to

The value of 1+sum_(k=0)^(12){(cos((2k+1)pi))/(13)+i(sin((2k+1)pi))/(13)}