If `alpha = pi/3`, prove that `cos alpha*cos 2alpha*cos 3alpha*cos 4alpha*cos 5alpha*cos 6alpha = -1/16`.

cos2 alpha-cos3alpha-cos4alpha+cos5alpha simplifies to :

cos alpha cos 2 alpha cos 4 alpha cos 8 alpha = (1)/(16), if alpha = 24 ^(@)

1/(cosalpha+cos3alpha)+1/(cosalpha+cos5alpha)....1/(cosalpha+cos(2n+1)alpha

(cos alpha + 2 cos 3 alpha + cos 5 alpha )/(cos 3 alpha + 2 cos 5 alpha + cos 7 alpha ) = cos 3 alpha sec 5 alpha .

In Delta ABC , prove that c cos (A - alpha) + a cos (C + alpha) = b cos alpha

Evaluate cos alpha cos 2 alpha cos 3 alpha..........cos 999alpha , where alpha=(2pi)/(1999)

The value of (sin5alpha-sin3alpha)/(cos5alpha+2cos4alpha+cos3alpha) is

Prove by using principle of induction that: cos alpha+cos 2alpha+…+cos n alpha = sin. (nalpha)/2 cosec alpha/2 cos. ((n+1)alpha)/2

If alpha+beta= 60^0 , prove that cos^2 alpha + cos^2 beta - cosalpha cos beta = 3/4 .

Prove that : cos^2alpha+cos^2(alpha+beta)-2cosalphacosbetacos(alpha+beta)=sin^2beta