Vertex x-Coordinate of a Parabola
h=−2abDiscriminant of a Quadratic
Δ=b2−4acVertex y-Coordinate of a Parabola
k=c−4ab2Completing the Square: the Constant Needed
k=(2b)2Quadratic Formula (Positive Root)
x=2a−b+b2−4acQuadratic Formula (Negative Root)
x=2a−b−b2−4acSum of the Roots of a Quadratic
S=−abProduct of the Roots of a Quadratic
P=acDisplacement (Uniform Acceleration)
d=v0t+21at2Projectile Maximum Height
H=2gv02sin2θProjectile Time of Flight
T=g2v0sinθExponential Growth
A=A0(1+r)tExponential Decay
A=A0(1−r)tPercent Change
c=xoldxnew−xoldDeclining-Balance Depreciation (Book Value)
B=C(1−d)kHalf-Life Decay
N=N0(21)t/t1/2Half-Life and Decay Constant
t1/2=λln2Exponential Growth by Doubling Time
N=N0⋅2t/TRule of 72 (Doubling Time)
n≈i0.72Solve an Exponential Equation for the Exponent
x=lnbln(y/a)Logarithm Change of Base
logbx=lnblnxPeriod-Frequency Relation
T=f1Wave Speed (v = fλ)
v=fλSimple Pendulum Period
T=2πgLSpeed in Circular Motion (v = 2πr/T)
v=T2πrSHM Displacement at Time t
x=Acos(ωt)Period of a Spring-Mass Oscillator
T=2πkmRight-Triangle Sine Ratio (SOH)
sinθ=hoRight-Triangle Cosine Ratio (CAH)
cosθ=haRight-Triangle Tangent Ratio (TOA)
tanθ=aoPythagorean Theorem
a2+b2=c2Law of Sines
sinAa=sinBbLaw of Cosines
c2=a2+b2−2abcosCTriangle Area (Two Sides and Included Angle)
A=21absinCArithmetic Sequence nth Term
an=a1+(n−1)dGeometric Sequence nth Term
an=a1rn−1Arithmetic Series Sum
Sn=2n(2a1+(n−1)d)Geometric Series Sum
Sn=1−ra1(1−rn)Simple Interest
I=PrtCompound Interest (Periodic)
A=P(1+nr)ntPresent Value
PV=(1+r)tFVFuture Value of an Annuity (Regular Deposits)
FV=Di(1+i)n−1Loan Payment (Amortized Loan or Mortgage)
M=1−(1+i)−nPi