a² + b² = c² ∫ f(x) dx sin²x + cos²x = 1 D = b² − 4ac π ≈ 3,14 Σ √x x₁ + x₂ = −p log₂ 8 = 3 (a+b)² y = kx + b ∞ f′(x) Δ aₙ = a₁ + (n−1)d %