`16(costheta-cospi/8)(costheta-cos(3pi)/8)(costheta-cos(5pi)/8)(costheta-cos(7pi)/8)=lambdacos4theta,` then the value of `lambda` is _____.

Let f( theta) = ( cos theta - "cos" (pi)/(8))(cos theta - "cos" (3 pi)/(8))(cos theta - "cos" (5 pi)/(8) )(cos theta - "cos" (7pi)/(8)) then :

costheta-cos2theta=sin3theta

costheta.cos2theta.cos3theta=1/4

If sin((pi)/(4)costheta)=cos((pi)/(4)tantheta), then theta is equal to

If cos7theta=costheta-sin4theta , then the general value of theta is

5cos theta+3cos(theta-(pi)/(3))+8=

If (costheta+sintheta)/(costheta-sintheta)=8 then the value of cot theta is equal to:

Solve the equation z^8+1=0 and deduce that cos4theta=8(costheta-cos(pi/8))(costheta-cos((3theta)/3))(costheta- cos((5pi)/8))(costheta-cot((7pi)/8))

(1+cos.(pi)/(8))(1+cos.(3pi)/(8))(1+cos.(5pi)/(8))(1+cos.(7pi)/(8)) is equal to