`"sin" pi/12 "sin" (5pi)/12=`

Prove that (i) " 2sin " (5pi)/(12) " sin " (pi)/(12)=(1)/(2) (ii) " 2 cos " (5pi)/(12) " cos " .(pi)/(12)=(1)/(2) (iii) " 2 sin ".(5pi)/(12) " cos " (pi)/(2) = ((2+sqrt(3))/(2))

Prove that (i) " 2sin " (5pi)/(12) " sin " (pi)/(12)=(1)/(2) (ii) " 2 cos " (5pi)/(12) " cos " .(pi)/(12)=(1)/(2) (iii) " 2 sin ".(5pi)/(12) " cos " (pi)/(2) = ((2+sqrt(3))/(2))

Prove that; 2(sin(5 pi))/(12)(sin pi)/(12)=(1)/(2)

Prove that 2"sin"(5pi)/(12)"cos"(pi)/(12)=(sqrt3+2)/2

"sin"pi/14" sin"(3pi)/14" sin"(5pi)/14" sin"(7pi)/5=

The value of sin\ pi/16 sin\ (3pi)/16 sin\ (5pi)/16 sin\ (7pi)/16 is

Which of the following quantities are rational? (a) sin((11pi)/(12))sin((5pi)/(12)) (b) cos e c((9pi)/(10))sec((4pi)/5) (c) sin^4(pi/8)+cos^4(pi/8) (d) (1+cos((2pi)/9))(1+cos((4pi)/9))(1+cos((8pi)/9))