If ` cos theta =(1)/(2)(a+(1)/(a))`, then `cos 2 theta =`

If cos theta=(1)/(2)(a+(1)/(a)), show that cos2 theta=(1)/(2)*(a^(2)+(1)/(a^(2)))

If cos theta=(1)/(2)(a+(1)/(a)) and cos3 theta=(1)/(2)(a^(k)+(1)/(a^(k))) then number of natural numbers 'k' less than 50 is

If cos theta =1/2(a+1/a) , prove that : 2 cos 2 theta= a^2+1/ a^2 .

If cos theta =1/2(a+1/a) , prove that : 2 cos 4 theta= a^4+1/ a^4 .

If theta =(pi)/(2 ^(n) +1), then cos theta cos 2 theta cos 2^(2) theta …cos 2 ^(n-1)theta is equal to

If cos theta=(1)/(2)(alpha+(1)/(alpha)) ,prove that: (i) 2 cos 2theta=alpha^(2)+(1)/(alpha^(2)) (ii) 2 cos 4theta=alpha^(4)+(1)/(alpha^(4)) .

|2sin theta-csc theta|>=1 and theta!=(n pi)/(2),n in Z|2sin theta-csc theta|>=1 and theta!=(n pi)/(2),n in Z then cos2 theta>=(1)/(2)(b)cos2 theta>=(1)/(4)cos2 theta<=(1)/(2)(d)cos2 theta<=(1)/(4)

If cos theta _(1) = 2 cos theta _(2), then tan (( theta _(1) + theta _(2))/(2)) tan (( theta _(1) - theta _(2))/(2)) is equal to

Prove that : (2 cos 2^n theta + 1)/(2 cos theta +1) = (2 cos theta -1) (2 cos 2theta -1) (2 cos 2^2 theta -1) … (2 cos 2^(n-1) theta -1)

Prove that : (2 cos 2^n theta + 1)/(2 cos theta +1) = (2 cos theta -1) (2 cos 2theta -1) (2 cos 2^2 theta -1) … (2 cos 2^(n-1) theta -1)