cos2^(3)(pi)/(10)cos2^(4)(pi)/(10)cos2^(5)(pi)/(10)....cos2^(10)(pi)/(10)" is equal to "

Given , cos2^(m)thetacos2^(m+1)theta......cos2^ntheta=(sin2^(n+1)theta)/(2^(n-m+1)sin2^(m) theta) where 2^mtheta ne kpi,n,m,k in l solve the following cos2^(3)""(pi)/10cos2^(4)""(pi)/10cos2^(5)""(pi)/10.....cos2^(10)""(pi)/10 is equal to

(sin((pi)/(10))+sin(13(pi)/(10)))(cos^(2)((pi)/(6))-cos^(2)((pi)/(10))) is equal to

Show that cos^(2)""(pi)/(10)+cos^(2)""(4pi)/(10)+cos^(2)""(6pi)/10+cos^(2)""(9pi)/10=2 .

cos((pi)/(15))cos((2 pi)/(15))cos((pi)/(5))cos((4 pi)/(15))cos((2 pi)/(5))cos((7 pi)/(15)) is equal to

The value of cos((pi)/(10))cos((2 pi)/(10))cos((4 pi)/(10))cos((8 pi)/(10))cos((16 pi)/(10))

The value of 4cos((pi)/(10))-3sec((pi)/(10))-2tan((pi)/(10))is equal to

Statement-1: cos((pi)/(10))cos((2pi)/(10))cos((4pi)/(10))=(cos((8pi)/(10)))/(2^(3)sin((pi)/(10))) Statement-2: cos A.cos2A.cos2^(2)A.......cos(2^(n-1)A)=(sin(2^(n)A))/(2^(n)sinA)