solve sin(x)=0 on [0,2*pi]
Let's solve in ℝ: sin(x) = 0
sin(θ) = 0 is equivalent to: θ = kπ, k ∈ ℤ
Solution found: x = kπ
For x = kπ, 0 ≤ k ≤ 2. In [0, 2π], we keep the solutions lying in the interval: { 0, π, 2π }
▶Solution:   x = { 0, π, 2π }
The numeric value of: x = { 0, π, 2π } is:
x = { 0, ≈ 3.1416, ≈ 2·3.1416 }
▷ x = { 0, ≈ 3.1416, ≈ 6.2832 }