If `cos(theta - alpha) , costheta , cos(theta + alpha)` are in H.P. then `costheta.sec(alpha)/2 = `

If cos(theta-alpha),cos theta,cos(theta+alpha) are in H.P. then cos theta.(sec(alpha))/(2)=

If cos(theta-alpha),costheta,cos(theta+alpha) are in H.P.,then costhetasec(alpha//2) is equal to

If cos (theta - alpha),cos(theta),Cos(theta + alpha) are in H.P. and cos alpha ne 1 , then angle alpha lie in the

If sec(2 theta-2 alpha),(1)/(2)cos ec^(2)theta,sec(2 theta+2 alpha) are in H.P. then

if sin(theta+alpha)=cos(theta+alpha) then tan alpha

If sec(theta-alpha), sectheta and sec(theta+alpha) are in AP, where cos alpha ne 1 then what is the value of sin^2 theta + cos alpha ?

If cos 3 theta = alpha cos theta + beta cos ^(3) theta, then (alpha, beta) =

If cos (theta - alpha) = a, cos (theta - beta) = b , then the value of sin^(2) (alpha - beta) + 2ab cos (alpha - beta) is