━━ ALGEBRA ━━ Quadratic Formula: x = (−b ± √(b²−4ac)) / 2a AP nth term: aₙ = a + (n−1)d AP Sum: Sₙ = n/2 · [2a + (n−1)d] GP nth term: aₙ = ar^(n−1) GP Sum: Sₙ = a(rⁿ−1)/(r−1) ━━ TRIGONOMETRY ━━ Identities: sin²θ + cos²θ = 1 1 + tan²θ = sec²θ 1 + cot²θ = cosec²θ Values: sin30°=½ cos30°=√3/2 tan30°=1/√3 sin45°=cos45°=1/√2 tan45°=1 sin60°=√3/2 cos60°=½ tan60°=√3 Addition: sin(A+B) = sinAcosB + cosAsinB ━━ COORDINATE GEOMETRY ━━ Distance: d = √((x₂-x₁)² + (y₂-y₁)²) Midpoint: M = ((x₁+x₂)/2, (y₁+y₂)/2) Section formula: (mx₂+nx₁)/(m+n), (my₂+ny₁)/(m+n) Slope: m = (y₂-y₁)/(x₂-x₁) = tanθ ━━ MENSURATION ━━ Circle: A = πr², C = 2πr Sphere: SA = 4πr², V = 4/3πr³ Cylinder: V = πr²h, CSA = 2πrh Cone: V = 1/3πr²h, l = √(r²+h²) Cuboid: V = lbh, TSA = 2(lb+bh+hl) ━━ STATISTICS ━━ Mean (grouped): x̄ = Σfx / Σf Median: l + [(n/2 − cf)/f] × h Mode: l + [(f₁−f₀)/(2f₁−f₀−f₂)] × h