The set of values of `k in R` such that the equation `cos 2theta+ cos theta + k=0` admits a solution for theta is

The set of values of k in R such that the equation cos2 theta+cos theta+k=0 admits a solution for theta is

The set of values of lambda in R such that sin^(2) theta + cos theta = lambda cos^(2) theta holds for some theta , is

The solution set of sin 3theta + cos 2theta = 0 iss

The equation K-sin theta+cos2 theta=2k-7 possesses a real solution if

If cos theta + cos 2theta + cos 3theta = 0 then theta =

The solution set of sec theta = 2 cos theta is