cos(-(9 pi)/(4))=

Cos (-(9pi)/(4))=

Cos (-(9pi)/(4))=

Prove that: i) sin(5pi)/(18) - cos(4pi)/(9) = sqrt(3)sinpi/9 ii) cos(3pi)/4+A-cos((3pi)/(4)-A)=-sqrt(2)sinA

Prove that: i) sin(5pi)/(18) - cos(4pi)/(9) = sqrt(3)sinpi/9 ii) cos(3pi)/4+A-cos((3pi)/(4)-A)=-sqrt(2)sinA

The number of roots of the equation sin(2x+(pi)/(18))cos(2x-(pi)/(9))=-(1)/(4) in [0,2 pi] is

The value of cos^(-1){(1)/(sqrt(2))(cos((9 pi)/(10))-sin((9 pi)/(10)))}

The principal solution of cos^(-1)(cos((9pi)/4)) is

The sum cos((pi)/(9))+cos((4 pi)/(9))+cos((3 pi)/(9))+......+cos((17 pi)/(9)) equals -

The value of (1+cos((pi)/(9)))(1+cos((3 pi)/(9)))(1+cos((5 pi)/(9)))(1+cos((7 pi)/(9)))

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