If sin A = ⁴/₅ and cos B = -¹²/₁₃, where A and B tie in first and third quadrant respectively, then cos (A + B) is equal to

The value of x for the maximum value of√3 cos x + sin x, is

The value of Cos²θ + Sec²θ is always

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

The value of cot (45^o + θ)  cot  (45^o - θ) is:

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

The expression tan²∝+ cot² ∝ 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 sin A sin (60^o-A) sin (60^o +A) is equal to

The value of sin 20^o sin 40^o sin 60^o sin 80^o is equal to