9x^(2)-7((4 pi)/(9)+7)-cos((4 pi)/(9)+7)sin((pi)/(9)+7)=(sqrt(3))/(2)

Prove that: sin((4 pi)/(9)+7)cos((pi)/(9)+7)-cos((4 pi)/(9)+7)sin((pi)/(9)+7)=(sqrt(3))/(2)

Prove that: sin((4pi)/9+7)cos(pi/9+7)-cos((4pi)/9+7)sin("pi/9+7)=(sqrt(3))/2

Prove that (i) "sin " (7pi)/(12) " cos " (pi)/(2) - "cos " *(7pi)/(12) " sin " (pi)/(4) = (sqrt(3))/(2) (ii) " sin " (pi)/(4) " cos " (pi)/(2) + "cos"(pi)/(4) " sin " (pi)/(12) = (sqrt(3))/(2) (iii) " cos " (2pi)/(3) " cos " (pi)/(4) - " sin " (2pi)/(3) " sin " (pi)/(4) =(-(sqrt(3) +1))/(2sqrt(2))

(sin((2 pi)/(7))+sin((4 pi)/(7)) -sin((6 pi)/(7)))/(sin((pi)/(7))sin((3 pi)/(7))sin((5 pi)/(7))) is equal to

Prove that (sin(-(11pi)/(3))tan((35pi)/(6))sec(-(7pi)/(3)))/(cos((5pi)/(4))cosc((7pi)/(4))cos((17pi)/(6)))= (2)/(sqrt(3))

(sin ((3 pi) / (7)) cos ((4 pi) / (7))) / (sin ((pi) / (7)))

If A=sin((2 pi)/(7))+sin((4 pi)/(7))+sin((8 pi)/(7)) and B=cos((2 pi)/(7))+cos((4 pi)/(7))+cos((8 pi)/(7)) then sqrt(A^(2)+B^(2)) is equal to

(sin (3 (pi) / (7)) cos (4 (pi) / (7))) / (sin ((pi) / (7)))

Prove that, sin^(2)((pi)/(18))+sin^(2)((pi)/(9))+sin^(2)((7pi)/(18))+sin^(2)((4pi)/(9))=2