Fill `1-cos2theta=.....`

cos theta+cos2 theta+cos3 theta+......+cos(n-1)theta+cos n theta=

(1+sin 2theta+cos 2theta)/(1+sin2 theta-cos 2 theta) =

Prove the following 1.((1-cos^(2)theta)/(sin^(2)theta))=12.1-((cos^(2)theta)/(1+sin theta))=sin theta

(1+sin2theta+cos2theta)/(1+sin2theta-cos2theta) =

If pi/2

If pi

If cos theta + (1)/(cos theta) = 4 , then prove that cos^(2) theta + (1)/(cos^(2)theta) = 14.

Prove that: (2cos2^(n)theta+1)/(2cos theta+1)=(2cos theta-1)(2cos2 theta-1)(2cos2^(2)theta-1)...(2cos2^(n-1)theta-1)

Prove that: (2cos2 theta+1)/(2cos theta+1)=(2cos theta-1)(2cos2 theta-1)(2cos2^(2)theta-1)...(2cos2^(n-1)theta-1)

(1+sin2 theta-cos2 theta)/(1+sin2 theta+cos2 theta)=tan theta