σ = 0.391 (slider from 0.0010 to 2, step 0.01)
μ = 0 (slider from -5 to 5, step 0.1)
fg = Function(1 / (σ * sqrt(2 * π)) * ℯ^((-(x - μ)^(2)) / (2 * σ^(2))), -10, 10)
mm: fg(μ)
y2: y = mm / 2
I = Intersect(fg, y2, (-0.46036731880355, 0.510156368799787))
lg: 2 * abs(x(I))