" 1."4cos6 theta cos4 theta cos2 theta=

4 cos 6 theta cos 4 theta cos 2 theta =

1+cos2 theta+cos4 theta+cos6 theta=

Find the values of theta betwen 0^(@) and 180^(@) satisying the equation cos6 theta+cos4 theta+cos2 theta+1=0

If : cos 6 theta + cos 4 theta + cos 2 theta + 1 = 0 , where, 0 lt theta lt 180^(@) , then : theta =

Prove that: (cos6 theta+6cos4 theta+15cos2 theta+10)/(cos5 theta+5cos3 theta+10cos theta)=2cos theta

Prove the following : cos 7 theta + cos 5 theta + cos 3 theta +cos theta =4 cos theta cos2 theta cos4 theta for all value of theta .

Prove the following : cos 3 theta+ cos 5 theta+ cos 7 theta+ cos 9 theta= 4 cos theta cos 2 theta cos 6 theta .

If theta=(pi)/(9), prove that cos theta cos2 theta cos3 theta cos4 theta=(1)/(16)

If cos theta cos 2 theta cos 3theta = 1//4 for 0 lt theta lt pi then theta =

1+ cos 2 theta + cos 4 theta + cos 6 theta =