If `A=[(1,tan(theta/2)),(-tan(theta/2),1)] and AB=I, then B=` (A) `{cos^2 (theta/2)}A` (B) `{cos^2(theta/2)}A\'` (C) `{cos^2(theta/2)}I` (D) none of these

c(1+cos2theta)= (A) c 2sin^2theta (B) c2cos^2theta (C) c2tan^2theta (D) none of these

If [(1,-tantheta),(tantheta,1)][(1,tantheta),(-tantheta,1)]^(-1)=[(a,-b),(b, a)] , then a=1,\ \ b=0 (b) a=cos2\ theta,\ \ b=sin2\ theta (c) a=sin2\ theta,\ \ b=cos2theta (d) none of these

The value of cos^4theta+sin^4theta-6cos^2theta is (a) cos2theta (b) sin2theta (c) cos4theta (d) none of these

If 3 tan theta tan phi=1 , then prove that 2 cos (theta+phi)=cos (theta-phi) .

Show that (1+tan .theta/2)/(1-tan. theta/2)=(1+sintheta)/(cos theta)=tan(pi/4+theta/2)

If tan^(4)theta +tan^(2) theta = 2 , then the value of cos^(4)theta +cos^(2)theta is-

If sintheta+sin^2theta=1 , then cos^2theta+cos^4theta= (a) -1 (b) 1 (c) 0 (d) None of these

Prove: tan^2thetacos^2theta=1-cos^2theta

a sin^(2) theta + b cos^(2) theta =c implies tan^(2) theta =

If cos theta=cos alpha cos beta then tan((theta+alpha)/2) tan((theta-alpha)/2)= (i) tan^2(alpha/2) (ii) tan^2(beta/2) (iii) tan^2(theta/2) (iv) cot^2(beta/2)