3) S=∫ₐᵇ|sin(x)|dx = ∫ₐᵇ(-sin(x))dx = cos(x)|ₐᵇ = cos(3π/2) - cos(7π/6) =
= 0 - cos(π + π/6) = cos(π/6) = √3/2 ≈ 0.866
4) S = ∫₋₂⁰(x²+4x+5) + ∫₀⁴(x²-4x+5) = ((x³/3)+2x²+5x)|₋₂⁰ + ((x³/3)-2x²+5x)|₀⁴ =
= (8/3)-8+10 + (64/3)-32+20 = (14/3) + (28/3) = 42/3 = 14
