If tan α + tan β = 1 - tan α.tan β, where tan α tan β ≠ 1, then which of the following is one of the values of (α + β) ?

If (1 + tan θ) (1 + tan 9θ) = 2, then what is the value of tan(10θ)?

What is the value of sin 0° + sin 10° + sin 20° + sin 30° + ⋯ + sin 360°?

Consider all the subsets of the set A = {1, 2, 3, 4}. How many of them are supersets of the set {4}?