If `P=cospi/(20)dotcos(3pi)/(20)dotcos(7pi)/(20)dotcos(9pi)/(20)&Q=cospi/(11)dotcos(2pi)/(11)dotcos(8pi)/(11)dotcos(16pi)/(11),` then `P/Q` is not defined (b) 1 (c) 2 (d) None of these

If P=cospi/(20)dotcos(3pi)/(20)dotcos(7pi)/(20)dotcos(9pi)/(20)&Q=cospi/(11)dotcos(2pi)/(11)dotcos(4pi)/11dotcos(8pi)/(11)dotcos(16pi)/(11), then P/Q is (a) not defined (b) 1 (c) 2 (d) None of these

If P=cos(pi)/(20)*cos(3 pi)/(20)*cos(7 pi)/(20)*cos(9 pi)/(20)&Q=cos(pi)/(11)*cos(2 pi)/(11)*cos(8 pi)/(11)*cos(16 pi)/(11) , then (P)/(Q) is not defined (b) 1 (c) 2 (d) None of these

cos(pi/11) cos((2pi)/11) cos((3pi)/11)....cos((11pi)/11)=

cos (pi)/(11)+cos (3 pi)/(11)+cos (5 pi)/(11)+cos (7 pi)/(11)+cos (9 pi)/(11)=

cos(pi)/(11)+cos(3 pi)/(11)+cos(5 pi)/(11)+cos(7 pi)/(11)+cos(9 pi)/(11)=(1)/(2)

cos(pi)/(11)+cos(3 pi)/(11)+......cos(9 pi)/(11)=(1)/(2)

Show that cos(pi/11)cos((2pi)/11)cos((3pi)/11)cos((4pi)/11)cos((5pi)/11)=1/32

Show that cos(pi/11)+cos((3pi)/11)+cos((5pi)/11)+cos((7pi)/11)+cos((9pi)/11)=1/2

cot(pi/20).cot((3pi)/20)cot((5pi)/20)cot((7pi)/20)cot((9pi)/20)=....