The value of 1+ cos 56^o + cos 58^o - cos 66^o is equal to

The minimum value of 5 sin²θ + 4 cos²θ is

The value of cos 15^o is

If sin θ  + cosec θ = 2, then sin² θ + cosec² θ is equal to

If tan A = - ¹/₂ and tan B = - ¹/₃, then A+B =

The value of sin A sin (60^o-A) sin (60^o +A) is equal to

(tan 7^o) (tan 23^o) (tan 60^o)(tan 67^o)(tan83^o) is

If sin θ + cos θ = m and sec θ + cosec θ = n, then n (m+1) (m-1)  is equal to

The value of Cos²θ + Sec²θ is always