Draw the loci
` r = a cos (theta - alpha)`

If alpha + beta + gamma = 2 theta , prove that cos theta + cos(theta- alpha) + cos(theta- beta) + cos(theta -gamma) = 4(cos (alpha/2) cos (beta/2) cos (gamma/2))

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

If sec(theta+alpha)+sec(theta-alpha)=2sec theta then show that cos^(2)theta=1+cos alpha

If sec(theta+alpha)+sec(theta-alpha)=2sec theta then show that cos^(2)theta=1+cos alpha

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