Formula & term reference

D = b²−4ac — determines quadratic roots count

Greatest common divisor / least common multiple

n! = 1·2·3·...·n — permutation count

Rate of change — tangent slope at a point

Area under curve / antiderivative

Power to raise the base to: log₂8 = 3

z = a + bi, where i² = −1

Quantity with direction: velocity, force

a·b = |a||b|cosθ — projection of one onto another

Number table for transforms and equation systems

Matrix scalar — transform volume, invertibility

Middle value of an ordered dataset

Mean squared deviation from the mean

Δx in units / δx = Δx/x as percent