`64cos^3 theta sin ^4theta=cos7theta-cos5theta-3cos3theta+3costheta`

64cos^(3)theta sin^(4)theta=cos7 theta-cos5 theta-3cos3 theta+3cos theta

costheta-cos2theta=sin3theta

Prove that, 64cos^(3) theta sin^(4) theta = cos 7 theta - cos 5 theta - 3 cos 3theta+3 cos theta

(cos3 theta+2cos5 theta+cos7 theta)/(cos theta+2cos3 theta+cos5 theta)=cos2 theta-sin2 theta tan3 theta

Prove that, If " "15 theta = pi, "show that," cos theta cos2 theta cos3theta cos 4theta cos5 theta cos6theta cos7theta =1/2^(7)

2cos theta-cos3 theta-cos5 theta-16cos^(3)theta sin^(2)theta=

2cos theta-cos3 theta-cos5 theta-16cos^(3)theta sin^(2)theta=

(sin3 theta+sin5 theta+sin7 theta+sin9 theta)/(cos3 theta+cos5 theta+cos7 theta+cos9 theta)

(sin3 theta+sin5 theta+sin7 theta+sin9 theta)/(cos3 theta+cos5 theta+cos7 theta+cos9 theta) is equal to tan3 theta(b)cot3 theta(c)tan6 theta(d)cot6 theta

Solve: costheta+cos3theta+cos5theta+cos7theta=0