`cos^2alpha+cos^2(alpha+120^0)+cos^2(alpha-120^0)=3/2`

x=sqrt(a^2cos^2alpha+b^2sin^2alpha)+sqrt(a^2sin^2alpha+b^2cos^2alpha) then x^2=a^2+b^2+2sqrt(p(a^2+b^2)-p^2) , where p is equal to (a) a^2cos^2alpha+ b^2sin^2alpha (b) a^2sin^2alpha+b^2cos^2alpha (c) (1/2)(a^2+b^2+(a^2-b^2)cos2alpha) (d) (1/2)(a^2+b^2-(a^2-b^2)cos2alpha)

(cos2 x - cos2 alpha)/(cos x - cos alpha)

The expression cos^2(alpha+beta)+cos^2(alpha-beta)-cos2alpha.cos2beta, is (a)independent of alpha (b) independent of beta (c)independent of alphaa n dbeta (d)dependent on alphaa n dbeta

If n=1,2,3,……. then cos alpha cos 2 alpha cos 4 alpha ……. Cos 2^(n-1) alpha is equal to

If cot^3alpha+cot^2alpha+cotalpha=1 then (a) cos2alpha.tanalpha=-1 (b) cos2alpha.tanalpha=1 (c) cos2alpha-tan2alpha=1 (d) cos2alpha-tan2alpha=-1

Prove that : cos^2 (beta-gamma) + cos^2 (gamma-alpha) + cos^2 (alpha-beta) =1+2cos (beta-gamma) cos (gamma-alpha) cos (alpha-beta) .

For alpha=pi/7 which of the following hold(s) good? (a) tanalphatan2alphatan3alpha=tan3alpha-tan2alpha-tanalpha (b) cos e calpha=cos e c2alpha+cos e c4alpha (c) cosalpha-cos2alpha+cos3alpha=1/2 (d) 8cosalphacos2alphacos4alpha=1

The value of int_0^(pi/2) sin|2x-alpha|dx, where alpha in [0,pi], is (a) 1-cos alpha (b) 1+cos alpha (c) 1 (d) cos alpha

Prove that 2 sin^2 beta + 4 cos(alpha + beta) sin alpha sin beta + cos 2(alpha + beta) = cos 2alpha

Prove that sin^2alpha-sin^4alpha= cos^2alpha-cos^4alpha