THE RIGHT FORMULA, RIGHT WHEN YOU NEED IT
Formula bank
432 formulas and useful rearrangements across your three subjects.
Showing 432 of 432 formulas
PhysicsKinematics
Average speed
v̄ = total distance / total time
PhysicsKinematics
Average speed · form 2
distance = v̄ × time
PhysicsKinematics
Average speed · form 3
time = distance / v̄
PhysicsKinematics
Average velocity
v̄ = displacement / time
PhysicsKinematics
Average velocity · form 2
displacement = v̄ × time
PhysicsKinematics
Average velocity · form 3
time = displacement / v̄
PhysicsKinematics
Acceleration
a = (v − u)/t
PhysicsKinematics
Acceleration · form 2
v = u + at
PhysicsKinematics
Acceleration · form 3
t = (v − u)/a
PhysicsKinematics
Uniform acceleration displacement
s = ut + ½at²
PhysicsKinematics
Uniform acceleration displacement · form 2
s = (u + v)t/2
PhysicsKinematics
Uniform acceleration displacement · form 3
v² = u² + 2as
PhysicsKinematics
Projectile horizontal range
R = u² sin(2θ)/g
PhysicsKinematics
Projectile horizontal range · form 2
Rmax = u²/g
PhysicsKinematics
Projectile horizontal range · form 3
u = √(Rg/sin(2θ))
PhysicsKinematics
Projectile maximum height
H = u² sin²θ/(2g)
PhysicsKinematics
Projectile maximum height · form 2
uᵧ = u sinθ
PhysicsKinematics
Projectile maximum height · form 3
H = uᵧ²/(2g)
PhysicsKinematics
Projectile flight time
T = 2u sinθ/g
PhysicsKinematics
Projectile flight time · form 2
uᵧ = gT/2
PhysicsKinematics
Projectile flight time · form 3
g = 2u sinθ/T
PhysicsDynamics
Newton's second law
Fnet = ma
PhysicsDynamics
Newton's second law · form 2
a = Fnet/m
PhysicsDynamics
Newton's second law · form 3
m = Fnet/a
PhysicsDynamics
Linear momentum
p = mv
PhysicsDynamics
Linear momentum · form 2
v = p/m
PhysicsDynamics
Linear momentum · form 3
m = p/v
PhysicsDynamics
Impulse
J = FΔt
PhysicsDynamics
Impulse · form 2
J = Δp
PhysicsDynamics
Impulse · form 3
Favg = Δp/Δt
PhysicsDynamics
Limiting friction
fmax = μsN
PhysicsDynamics
Limiting friction · form 2
μs = fmax/N
PhysicsDynamics
Limiting friction · form 3
N = fmax/μs
PhysicsDynamics
Centripetal acceleration
ac = v²/r
PhysicsDynamics
Centripetal acceleration · form 2
ac = ω²r
PhysicsDynamics
Centripetal acceleration · form 3
v = ωr
PhysicsDynamics
Centripetal force
Fc = mv²/r
PhysicsDynamics
Centripetal force · form 2
Fc = mω²r
PhysicsDynamics
Centripetal force · form 3
r = mv²/Fc
PhysicsEnergy
Work
W = Fs cosθ
PhysicsEnergy
Work · form 2
F = W/(s cosθ)
PhysicsEnergy
Work · form 3
s = W/(F cosθ)
PhysicsEnergy
Kinetic energy
K = ½mv²
PhysicsEnergy
Kinetic energy · form 2
v = √(2K/m)
PhysicsEnergy
Kinetic energy · form 3
m = 2K/v²
PhysicsEnergy
Gravitational potential energy
U = mgh
PhysicsEnergy
Gravitational potential energy · form 2
h = U/(mg)
PhysicsEnergy
Gravitational potential energy · form 3
m = U/(gh)
PhysicsEnergy
Power
P = W/t
PhysicsEnergy
Power · form 2
W = Pt
PhysicsEnergy
Power · form 3
P = Fv cosθ
PhysicsRotation
Torque
τ = rF sinθ
PhysicsRotation
Torque · form 2
F = τ/(r sinθ)
PhysicsRotation
Torque · form 3
τ = Iα
PhysicsRotation
Angular momentum
L = Iω
PhysicsRotation
Angular momentum · form 2
ω = L/I
PhysicsRotation
Angular momentum · form 3
I = L/ω
PhysicsRotation
Rotational kinetic energy
Krot = ½Iω²
PhysicsRotation
Rotational kinetic energy · form 2
I = 2Krot/ω²
PhysicsRotation
Rotational kinetic energy · form 3
ω = √(2Krot/I)
PhysicsRotation
Rolling without slipping
v = ωR
PhysicsRotation
Rolling without slipping · form 2
ω = v/R
PhysicsRotation
Rolling without slipping · form 3
R = v/ω
PhysicsGravitation
Newton's gravitation
F = Gm₁m₂/r²
PhysicsGravitation
Newton's gravitation · form 2
G = Fr²/(m₁m₂)
PhysicsGravitation
Newton's gravitation · form 3
r = √(Gm₁m₂/F)
PhysicsGravitation
Gravitational acceleration
g = GM/r²
PhysicsGravitation
Gravitational acceleration · form 2
M = gr²/G
PhysicsGravitation
Gravitational acceleration · form 3
r = √(GM/g)
PhysicsGravitation
Escape speed
vesc = √(2GM/R)
PhysicsGravitation
Escape speed · form 2
vesc = √(2gR)
PhysicsGravitation
Escape speed · form 3
g = vesc²/(2R)
PhysicsGravitation
Orbital speed
vorbit = √(GM/r)
PhysicsGravitation
Orbital speed · form 2
vorbit² = GM/r
PhysicsGravitation
Orbital speed · form 3
r = GM/vorbit²
PhysicsFluids
Hydrostatic pressure
P = ρgh
PhysicsFluids
Hydrostatic pressure · form 2
h = P/(ρg)
PhysicsFluids
Hydrostatic pressure · form 3
ρ = P/(gh)
PhysicsFluids
Buoyancy
Fb = ρfluid gVdisplaced
PhysicsFluids
Buoyancy · form 2
Vdisplaced = Fb/(ρfluid g)
PhysicsFluids
Buoyancy · form 3
ρfluid = Fb/(gVdisplaced)
PhysicsFluids
Continuity equation
A₁v₁ = A₂v₂
PhysicsFluids
Continuity equation · form 2
v₂ = A₁v₁/A₂
PhysicsFluids
Continuity equation · form 3
A₂ = A₁v₁/v₂
PhysicsThermal physics
Heat capacity
Q = mcΔT
PhysicsThermal physics
Heat capacity · form 2
c = Q/(mΔT)
PhysicsThermal physics
Heat capacity · form 3
ΔT = Q/(mc)
PhysicsThermal physics
Latent heat
Q = mL
PhysicsThermal physics
Latent heat · form 2
L = Q/m
PhysicsThermal physics
Latent heat · form 3
m = Q/L
PhysicsThermal physics
Ideal gas law
PV = nRT
PhysicsThermal physics
Ideal gas law · form 2
P = nRT/V
PhysicsThermal physics
Ideal gas law · form 3
T = PV/(nR)
PhysicsThermal physics
First law
ΔU = Q − Wby
PhysicsThermal physics
First law · form 2
Q = ΔU + Wby
PhysicsThermal physics
First law · form 3
Wby = Q − ΔU
PhysicsThermal physics
Carnot efficiency
η = 1 − Tc/Th
PhysicsThermal physics
Carnot efficiency · form 2
Tc = Th(1 − η)
PhysicsThermal physics
Carnot efficiency · form 3
Th = Tc/(1 − η)
PhysicsOscillations
Spring period
T = 2π√(m/k)
PhysicsOscillations
Spring period · form 2
f = (1/2π)√(k/m)
PhysicsOscillations
Spring period · form 3
k = 4π²m/T²
PhysicsOscillations
Pendulum period
T = 2π√(L/g)
PhysicsOscillations
Pendulum period · form 2
L = gT²/(4π²)
PhysicsOscillations
Pendulum period · form 3
g = 4π²L/T²
PhysicsWaves
Wave speed
v = fλ
PhysicsWaves
Wave speed · form 2
λ = v/f
PhysicsWaves
Wave speed · form 3
f = v/λ
PhysicsWaves
String wave speed
v = √(T/μ)
PhysicsWaves
String wave speed · form 2
T = μv²
PhysicsWaves
String wave speed · form 3
μ = T/v²
PhysicsElectricity
Coulomb's law
F = k|q₁q₂|/r²
PhysicsElectricity
Coulomb's law · form 2
k = Fr²/|q₁q₂|
PhysicsElectricity
Coulomb's law · form 3
r = √(k|q₁q₂|/F)
PhysicsElectricity
Electric field
E = F/q
PhysicsElectricity
Electric field · form 2
F = qE
PhysicsElectricity
Electric field · form 3
q = F/E
PhysicsElectricity
Electric potential
V = U/q
PhysicsElectricity
Electric potential · form 2
U = qV
PhysicsElectricity
Electric potential · form 3
q = U/V
PhysicsElectricity
Capacitance
C = Q/V
PhysicsElectricity
Capacitance · form 2
Q = CV
PhysicsElectricity
Capacitance · form 3
V = Q/C
PhysicsElectricity
Capacitor energy
U = ½CV²
PhysicsElectricity
Capacitor energy · form 2
U = Q²/(2C)
PhysicsElectricity
Capacitor energy · form 3
U = ½QV
PhysicsElectricity
Ohm's law
V = IR
PhysicsElectricity
Ohm's law · form 2
I = V/R
PhysicsElectricity
Ohm's law · form 3
R = V/I
PhysicsElectricity
Resistance of wire
R = ρL/A
PhysicsElectricity
Resistance of wire · form 2
ρ = RA/L
PhysicsElectricity
Resistance of wire · form 3
A = ρL/R
PhysicsElectricity
Electrical power
P = VI
PhysicsElectricity
Electrical power · form 2
P = I²R
PhysicsElectricity
Electrical power · form 3
P = V²/R
PhysicsMagnetism
Magnetic force on charge
F = qvB sinθ
PhysicsMagnetism
Magnetic force on charge · form 2
B = F/(qv sinθ)
PhysicsMagnetism
Magnetic force on charge · form 3
v = F/(qB sinθ)
PhysicsMagnetism
Magnetic force on wire
F = BIL sinθ
PhysicsMagnetism
Magnetic force on wire · form 2
B = F/(IL sinθ)
PhysicsMagnetism
Magnetic force on wire · form 3
I = F/(BL sinθ)
PhysicsMagnetism
Flux
Φ = BA cosθ
PhysicsMagnetism
Flux · form 2
B = Φ/(A cosθ)
PhysicsMagnetism
Flux · form 3
A = Φ/(B cosθ)
PhysicsMagnetism
Faraday induction
ε = −NΔΦ/Δt
PhysicsMagnetism
Faraday induction · form 2
|ε| = N|ΔΦ|/Δt
PhysicsMagnetism
Faraday induction · form 3
|ΔΦ| = |ε|Δt/N
PhysicsAC circuits
RMS values
Vrms = Vpeak/√2
PhysicsAC circuits
RMS values · form 2
Vpeak = √2 Vrms
PhysicsAC circuits
RMS values · form 3
Irms = Ipeak/√2
PhysicsOptics
Refractive index
n = c/v
PhysicsOptics
Refractive index · form 2
v = c/n
PhysicsOptics
Refractive index · form 3
c = nv
PhysicsOptics
Snell's law
n₁ sin i = n₂ sin r
PhysicsOptics
Snell's law · form 2
sin r = n₁ sin i/n₂
PhysicsOptics
Snell's law · form 3
n₂ = n₁ sin i/sin r
PhysicsOptics
Thin lens equation
1/f = 1/v − 1/u
PhysicsOptics
Thin lens equation · form 2
1/v = 1/f + 1/u
PhysicsOptics
Thin lens equation · form 3
1/u = 1/v − 1/f
PhysicsOptics
Lens power
P = 1/f (f in metres)
PhysicsOptics
Lens power · form 2
f = 1/P (metres)
PhysicsOptics
Lens power · form 3
Ptotal = P₁ + P₂
PhysicsOptics
Interference fringe width
β = λD/d
PhysicsOptics
Interference fringe width · form 2
λ = βd/D
PhysicsOptics
Interference fringe width · form 3
d = λD/β
PhysicsModern physics
Photon energy
E = hν
PhysicsModern physics
Photon energy · form 2
E = hc/λ
PhysicsModern physics
Photon energy · form 3
ν = c/λ
PhysicsModern physics
Photoelectric equation
Kmax = hν − φ
PhysicsModern physics
Photoelectric equation · form 2
φ = hν − Kmax
PhysicsModern physics
Photoelectric equation · form 3
eVstop = Kmax
PhysicsModern physics
de Broglie wavelength
λ = h/p
PhysicsModern physics
de Broglie wavelength · form 2
p = h/λ
PhysicsModern physics
de Broglie wavelength · form 3
λ = h/(mv)
PhysicsModern physics
Radioactive decay
N = N₀e^(−λt)
PhysicsModern physics
Radioactive decay · form 2
A = λN
PhysicsModern physics
Radioactive decay · form 3
t½ = ln 2/λ
PhysicsModern physics
Mass-energy equivalence
E = mc²
PhysicsModern physics
Mass-energy equivalence · form 2
m = E/c²
PhysicsModern physics
Mass-energy equivalence · form 3
ΔE = Δmc²
ChemistryMole concept
Moles from mass
n = m/M
ChemistryMole concept
Moles from mass · form 2
m = nM
ChemistryMole concept
Moles from mass · form 3
M = m/n
ChemistryMole concept
Particle count
N = nNA
ChemistryMole concept
Particle count · form 2
n = N/NA
ChemistryMole concept
Particle count · form 3
NA = N/n
ChemistryMole concept
Molarity
C = n/V(L)
ChemistryMole concept
Molarity · form 2
n = CV
ChemistryMole concept
Molarity · form 3
V(L) = n/C
ChemistryMole concept
Molality
b = nsolute/kg solvent
ChemistryMole concept
Molality · form 2
nsolute = b × kg solvent
ChemistryMole concept
Molality · form 3
kg solvent = nsolute/b
ChemistryMole concept
Mole fraction
xA = nA/(nA+nB)
ChemistryMole concept
Mole fraction · form 2
xA + xB = 1
ChemistryMole concept
Mole fraction · form 3
nA/nB = xA/xB
ChemistryAtomic structure
Photon frequency
ν = c/λ
ChemistryAtomic structure
Photon frequency · form 2
λ = c/ν
ChemistryAtomic structure
Photon frequency · form 3
E = hν
ChemistryAtomic structure
Bohr energy
En = −13.6Z²/n² eV
ChemistryAtomic structure
Bohr energy · form 2
ΔE = Ef − Ei
ChemistryAtomic structure
Bohr energy · form 3
|ΔE| = hν
ChemistryAtomic structure
Bohr radius
rn = a₀n²/Z
ChemistryAtomic structure
Bohr radius · form 2
r₁ = a₀/Z
ChemistryAtomic structure
Bohr radius · form 3
rn/r₁ = n²
ChemistryAtomic structure
Orbital capacity
Maximum electrons in shell n = 2n²
ChemistryAtomic structure
Orbital capacity · form 2
Orbitals in shell n = n²
ChemistryAtomic structure
Orbital capacity · form 3
Maximum electrons in subshell l = 2(2l+1)
ChemistryAtomic structure
Matter wavelength
λ = h/p
ChemistryAtomic structure
Matter wavelength · form 2
λ = h/(mv)
ChemistryAtomic structure
Matter wavelength · form 3
p = h/λ
ChemistryBonding
Formal charge
FC = valence − lone electrons − bonds
ChemistryBonding
Formal charge · form 2
sum of formal charges = net charge
ChemistryBonding
Formal charge · form 3
bond order = (bonding e⁻ − antibonding e⁻)/2
ChemistryBonding
Dipole moment
μ = qd
ChemistryBonding
Dipole moment · form 2
q = μ/d
ChemistryBonding
Dipole moment · form 3
d = μ/q
ChemistryGases
Ideal gas
PV = nRT
ChemistryGases
Ideal gas · form 2
P = nRT/V
ChemistryGases
Ideal gas · form 3
V = nRT/P
ChemistryGases
Combined gas law
P₁V₁/T₁ = P₂V₂/T₂
ChemistryGases
Combined gas law · form 2
P₂ = P₁V₁T₂/(T₁V₂)
ChemistryGases
Combined gas law · form 3
V₂ = P₁V₁T₂/(T₁P₂)
ChemistryGases
Dalton partial pressures
Ptotal = ΣPi
ChemistryGases
Dalton partial pressures · form 2
Pi = xiPtotal
ChemistryGases
Dalton partial pressures · form 3
xi = Pi/Ptotal
ChemistryGases
Gas density
ρ = PM/(RT)
ChemistryGases
Gas density · form 2
M = ρRT/P
ChemistryGases
Gas density · form 3
P = ρRT/M
ChemistryThermodynamics
Enthalpy relation
ΔH = ΔU + ΔngRT
ChemistryThermodynamics
Enthalpy relation · form 2
ΔU = ΔH − ΔngRT
ChemistryThermodynamics
Enthalpy relation · form 3
Δng = (ΔH − ΔU)/(RT)
ChemistryThermodynamics
Gibbs free energy
ΔG = ΔH − TΔS
ChemistryThermodynamics
Gibbs free energy · form 2
ΔH = ΔG + TΔS
ChemistryThermodynamics
Gibbs free energy · form 3
ΔS = (ΔH − ΔG)/T
ChemistryThermodynamics
Gibbs and equilibrium
ΔG° = −RT ln K
ChemistryThermodynamics
Gibbs and equilibrium · form 2
ln K = −ΔG°/(RT)
ChemistryThermodynamics
Gibbs and equilibrium · form 3
K = e^(−ΔG°/RT)
ChemistryThermodynamics
Calorimetry
q = mcΔT
ChemistryThermodynamics
Calorimetry · form 2
c = q/(mΔT)
ChemistryThermodynamics
Calorimetry · form 3
ΔT = q/(mc)
ChemistrySolutions
Raoult's law
PA = xA PA°
ChemistrySolutions
Raoult's law · form 2
xA = PA/PA°
ChemistrySolutions
Raoult's law · form 3
Ptotal = ΣxiPi°
ChemistrySolutions
Boiling point elevation
ΔTb = iKb b
ChemistrySolutions
Boiling point elevation · form 2
b = ΔTb/(iKb)
ChemistrySolutions
Boiling point elevation · form 3
i = ΔTb/(Kb b)
ChemistrySolutions
Freezing point depression
ΔTf = iKf b
ChemistrySolutions
Freezing point depression · form 2
b = ΔTf/(iKf)
ChemistrySolutions
Freezing point depression · form 3
i = ΔTf/(Kf b)
ChemistrySolutions
Osmotic pressure
π = iCRT
ChemistrySolutions
Osmotic pressure · form 2
C = π/(iRT)
ChemistrySolutions
Osmotic pressure · form 3
i = π/(CRT)
ChemistryEquilibrium
Reaction quotient
Q = product activities/reactant activities
ChemistryEquilibrium
Reaction quotient · form 2
Q < K: forward favored
ChemistryEquilibrium
Reaction quotient · form 3
Q > K: reverse favored
ChemistryEquilibrium
pH and pOH
pH = −log[H⁺]
ChemistryEquilibrium
pH and pOH · form 2
pOH = −log[OH⁻]
ChemistryEquilibrium
pH and pOH · form 3
pH + pOH = 14 (at 25°C)
ChemistryEquilibrium
Acid dissociation
Ka = [H⁺][A⁻]/[HA]
ChemistryEquilibrium
Acid dissociation · form 2
pKa = −log Ka
ChemistryEquilibrium
Acid dissociation · form 3
KaKb = Kw (conjugate pair)
ChemistryEquilibrium
Buffer equation
pH = pKa + log([A⁻]/[HA])
ChemistryEquilibrium
Buffer equation · form 2
[A⁻]/[HA] = 10^(pH−pKa)
ChemistryEquilibrium
Buffer equation · form 3
at [A⁻] = [HA], pH = pKa
ChemistryElectrochemistry
Standard cell potential
E°cell = E°cathode − E°anode
ChemistryElectrochemistry
Standard cell potential · form 2
ΔG° = −nFE°cell
ChemistryElectrochemistry
Standard cell potential · form 3
E°cell = (RT/nF) ln K
ChemistryElectrochemistry
Nernst equation
E = E° − (RT/nF)ln Q
ChemistryElectrochemistry
Nernst equation · form 2
E = E° − (0.0591/n)log Q at 298 K
ChemistryElectrochemistry
Nernst equation · form 3
at equilibrium E = 0
ChemistryElectrochemistry
Faraday electrolysis
Q = It
ChemistryElectrochemistry
Faraday electrolysis · form 2
m = MIt/(nF)
ChemistryElectrochemistry
Faraday electrolysis · form 3
m/M = Q/(nF)
ChemistryKinetics
First order rate
ln([A]₀/[A]) = kt
ChemistryKinetics
First order rate · form 2
[A] = [A]₀e^(−kt)
ChemistryKinetics
First order rate · form 3
t½ = 0.693/k
ChemistryKinetics
Zero order rate
[A] = [A]₀ − kt
ChemistryKinetics
Zero order rate · form 2
t½ = [A]₀/(2k)
ChemistryKinetics
Zero order rate · form 3
k = ([A]₀ − [A])/t
ChemistryKinetics
Arrhenius law
k = Ae^(−Ea/RT)
ChemistryKinetics
Arrhenius law · form 2
ln k = ln A − Ea/(RT)
ChemistryKinetics
Arrhenius law · form 3
ln(k₂/k₁) = (Ea/R)(1/T₁ − 1/T₂)
ChemistryKinetics
Rate law
rate = k[A]^m[B]^n
ChemistryKinetics
Rate law · form 2
overall order = m+n
ChemistryKinetics
Rate law · form 3
k = rate/([A]^m[B]^n)
ChemistryOrganic
Degree of unsaturation
DBE = (2C + 2 + N − H − X)/2
ChemistryOrganic
Degree of unsaturation · form 2
one ring contributes 1 DBE
ChemistryOrganic
Degree of unsaturation · form 3
one triple bond contributes 2 DBE
ChemistryOrganic
Chromatography ratio
Rf = distance of spot/distance of solvent
ChemistryOrganic
Chromatography ratio · form 2
distance of spot = Rf × solvent distance
ChemistryOrganic
Chromatography ratio · form 3
0 ≤ Rf ≤ 1 (typical planar chromatography)
ChemistryOrganic
Percentage yield
% yield = actual/theoretical × 100
ChemistryOrganic
Percentage yield · form 2
actual = theoretical × yield fraction
ChemistryOrganic
Percentage yield · form 3
theoretical = actual/yield fraction
ChemistryOrganic
Enantiomeric excess
ee = |%R − %S|
ChemistryOrganic
Enantiomeric excess · form 2
% major = (100 + ee)/2
ChemistryOrganic
Enantiomeric excess · form 3
% minor = (100 − ee)/2
ChemistryInorganic
Oxidation number sum
Σ oxidation states = ionic charge
ChemistryInorganic
Oxidation number sum · form 2
elemental substance has oxidation state 0
ChemistryInorganic
Oxidation number sum · form 3
monatomic ion oxidation state = ion charge
ChemistryInorganic
Coordination number
CN = number of donor atoms bonded to metal
ChemistryInorganic
Coordination number · form 2
metal oxidation state + ligand charges = complex charge
ChemistryInorganic
Coordination number · form 3
for octahedral complexes CN = 6
MathsAlgebra
Quadratic roots
x = (−b ± √(b²−4ac))/(2a)
MathsAlgebra
Quadratic roots · form 2
sum of roots = −b/a
MathsAlgebra
Quadratic roots · form 3
product of roots = c/a
MathsAlgebra
Discriminant
D = b² − 4ac
MathsAlgebra
Discriminant · form 2
D > 0: two distinct real roots
MathsAlgebra
Discriminant · form 3
D = 0: one repeated real root
MathsAlgebra
Difference of squares
a² − b² = (a−b)(a+b)
MathsAlgebra
Difference of squares · form 2
a² = (a+b)(a−b) + b²
MathsAlgebra
Difference of squares · form 3
b² = a² − (a−b)(a+b)
MathsAlgebra
Square of sum
(a+b)² = a² + 2ab + b²
MathsAlgebra
Square of sum · form 2
2ab = (a+b)² − a² − b²
MathsAlgebra
Square of sum · form 3
(a−b)² = a² − 2ab + b²
MathsAlgebra
Cube of sum
(a+b)³ = a³+3a²b+3ab²+b³
MathsAlgebra
Cube of sum · form 2
a³+b³ = (a+b)(a²−ab+b²)
MathsAlgebra
Cube of sum · form 3
a³−b³ = (a−b)(a²+ab+b²)
MathsAlgebra
Complex modulus
z = a+bi
MathsAlgebra
Complex modulus · form 2
|z| = √(a²+b²)
MathsAlgebra
Complex modulus · form 3
z z̄ = |z|²
MathsAlgebra
Complex polar form
z = r(cosθ+i sinθ)
MathsAlgebra
Complex polar form · form 2
r = |z|
MathsAlgebra
Complex polar form · form 3
arg(z₁z₂) = arg z₁ + arg z₂ (mod 2π)
MathsAlgebra
Arithmetic progression term
an = a + (n−1)d
MathsAlgebra
Arithmetic progression term · form 2
d = (an−a)/(n−1)
MathsAlgebra
Arithmetic progression term · form 3
a = an−(n−1)d
MathsAlgebra
Arithmetic progression sum
Sn = n(a+an)/2
MathsAlgebra
Arithmetic progression sum · form 2
Sn = n(2a+(n−1)d)/2
MathsAlgebra
Arithmetic progression sum · form 3
an = 2Sn/n − a
MathsAlgebra
Geometric progression term
an = ar^(n−1)
MathsAlgebra
Geometric progression term · form 2
r = an+1/an
MathsAlgebra
Geometric progression term · form 3
a = an/r^(n−1)
MathsAlgebra
Geometric progression sum
Sn = a(1−r^n)/(1−r)
MathsAlgebra
Geometric progression sum · form 2
S∞ = a/(1−r) for |r|<1
MathsAlgebra
Geometric progression sum · form 3
a = S∞(1−r)
MathsAlgebra
Binomial coefficient
nCr = n!/[r!(n−r)!]
MathsAlgebra
Binomial coefficient · form 2
nCr = nC(n−r)
MathsAlgebra
Binomial coefficient · form 3
nPr = nCr · r!
MathsAlgebra
Binomial theorem
(x+y)^n = Σ(nCr)x^(n−r)y^r
MathsAlgebra
Binomial theorem · form 2
sum of nCr from r=0 to n = 2^n
MathsAlgebra
Binomial theorem · form 3
alternating sum of nCr = 0 (n>0)
MathsAlgebra
Determinant 2×2
det[[a,b],[c,d]] = ad−bc
MathsAlgebra
Determinant 2×2 · form 2
inverse exists iff ad−bc ≠ 0
MathsAlgebra
Determinant 2×2 · form 3
det(AB) = det(A)det(B)
MathsFunctions
Function composition
(f∘g)(x) = f(g(x))
MathsFunctions
Function composition · form 2
(f∘g)⁻¹ = g⁻¹∘f⁻¹
MathsFunctions
Function composition · form 3
f(f⁻¹(x)) = x (on valid domain)
MathsTrigonometry
Pythagorean identity
sin²x + cos²x = 1
MathsTrigonometry
Pythagorean identity · form 2
1 + tan²x = sec²x
MathsTrigonometry
Pythagorean identity · form 3
1 + cot²x = csc²x
MathsTrigonometry
Angle addition sine
sin(A+B) = sin A cos B + cos A sin B
MathsTrigonometry
Angle addition sine · form 2
sin(A−B) = sin A cos B − cos A sin B
MathsTrigonometry
Angle addition sine · form 3
sin 2A = 2 sin A cos A
MathsTrigonometry
Angle addition cosine
cos(A+B) = cos A cos B − sin A sin B
MathsTrigonometry
Angle addition cosine · form 2
cos(A−B) = cos A cos B + sin A sin B
MathsTrigonometry
Angle addition cosine · form 3
cos 2A = cos²A − sin²A
MathsTrigonometry
Double-angle tangent
tan 2A = 2tan A/(1−tan²A)
MathsTrigonometry
Double-angle tangent · form 2
tan(A+B) = (tan A+tan B)/(1−tan A tan B)
MathsTrigonometry
Double-angle tangent · form 3
tan(A−B) = (tan A−tan B)/(1+tan A tan B)
MathsTrigonometry
Half angle
sin²(A/2) = (1−cos A)/2
MathsTrigonometry
Half angle · form 2
cos²(A/2) = (1+cos A)/2
MathsTrigonometry
Half angle · form 3
tan(A/2) = sin A/(1+cos A)
MathsCoordinate geometry
Distance in plane
d = √((x₂−x₁)²+(y₂−y₁)²)
MathsCoordinate geometry
Distance in plane · form 2
midpoint = ((x₁+x₂)/2,(y₁+y₂)/2)
MathsCoordinate geometry
Distance in plane · form 3
slope = (y₂−y₁)/(x₂−x₁)
MathsCoordinate geometry
Straight line
y−y₁ = m(x−x₁)
MathsCoordinate geometry
Straight line · form 2
y = mx+c
MathsCoordinate geometry
Straight line · form 3
x/a + y/b = 1
MathsCoordinate geometry
Point-line distance
d = |Ax₀+By₀+C|/√(A²+B²)
MathsCoordinate geometry
Point-line distance · form 2
parallel lines: A₁B₂−A₂B₁ = 0
MathsCoordinate geometry
Point-line distance · form 3
perpendicular lines: A₁A₂+B₁B₂ = 0
MathsCoordinate geometry
Circle equation
(x−h)²+(y−k)² = r²
MathsCoordinate geometry
Circle equation · form 2
centre = (h,k)
MathsCoordinate geometry
Circle equation · form 3
radius = √(h²+k²−c) for x²+y²−2hx−2ky+c=0
MathsCoordinate geometry
Parabola
y² = 4ax
MathsCoordinate geometry
Parabola · form 2
focus = (a,0) for y²=4ax
MathsCoordinate geometry
Parabola · form 3
directrix x = −a for y²=4ax
MathsCoordinate geometry
Ellipse
x²/a² + y²/b² = 1
MathsCoordinate geometry
Ellipse · form 2
c² = a²−b² (a>b)
MathsCoordinate geometry
Ellipse · form 3
e = c/a
MathsCoordinate geometry
Hyperbola
x²/a² − y²/b² = 1
MathsCoordinate geometry
Hyperbola · form 2
c² = a²+b²
MathsCoordinate geometry
Hyperbola · form 3
e = c/a
MathsCoordinate geometry
3D distance
d = √((Δx)²+(Δy)²+(Δz)²)
MathsCoordinate geometry
3D distance · form 2
midpoint = ((x₁+x₂)/2,(y₁+y₂)/2,(z₁+z₂)/2)
MathsCoordinate geometry
3D distance · form 3
direction cosines satisfy l²+m²+n²=1
MathsVectors
Dot product
a·b = |a||b|cosθ
MathsVectors
Dot product · form 2
a·b = a₁b₁+a₂b₂+a₃b₃
MathsVectors
Dot product · form 3
cosθ = (a·b)/(|a||b|)
MathsVectors
Cross product
|a×b| = |a||b|sinθ
MathsVectors
Cross product · form 2
a×b is perpendicular to a and b
MathsVectors
Cross product · form 3
parallelogram area = |a×b|
MathsCalculus
Derivative power rule
d(x^n)/dx = nx^(n−1)
MathsCalculus
Derivative power rule · form 2
d(c x^n)/dx = cnx^(n−1)
MathsCalculus
Derivative power rule · form 3
d(√x)/dx = 1/(2√x)
MathsCalculus
Derivative trigonometric
d(sin x)/dx = cos x
MathsCalculus
Derivative trigonometric · form 2
d(cos x)/dx = −sin x
MathsCalculus
Derivative trigonometric · form 3
d(tan x)/dx = sec²x
MathsCalculus
Derivative logarithmic
d(ln x)/dx = 1/x
MathsCalculus
Derivative logarithmic · form 2
d(e^x)/dx = e^x
MathsCalculus
Derivative logarithmic · form 3
d(a^x)/dx = a^x ln a
MathsCalculus
Product and quotient rules
(fg)' = f'g + fg'
MathsCalculus
Product and quotient rules · form 2
(f/g)' = (gf'−fg')/g²
MathsCalculus
Product and quotient rules · form 3
[f(g(x))]' = f'(g(x))g'(x)
MathsCalculus
Standard integrals
∫x^n dx = x^(n+1)/(n+1)+C (n≠−1)
MathsCalculus
Standard integrals · form 2
∫(1/x)dx = ln|x|+C
MathsCalculus
Standard integrals · form 3
∫e^x dx = e^x+C
MathsCalculus
Trig integrals
∫sin x dx = −cos x+C
MathsCalculus
Trig integrals · form 2
∫cos x dx = sin x+C
MathsCalculus
Trig integrals · form 3
∫sec²x dx = tan x+C
MathsCalculus
Integration by parts
∫u dv = uv − ∫v du
MathsCalculus
Integration by parts · form 2
∫ₐᵇ f(x)dx = F(b)−F(a)
MathsCalculus
Integration by parts · form 3
∫ₐᵇ f(x)dx = −∫ᵇₐ f(x)dx
MathsCalculus
Differential equation
dy/dx = ky ⇒ y = Ce^(kx)
MathsCalculus
Differential equation · form 2
dy/dx = f(x) ⇒ y = ∫f(x)dx+C
MathsCalculus
Differential equation · form 3
dy/y = k dx ⇒ ln|y| = kx+C
MathsProbability
Classical probability
P(A) = favorable/total equally likely
MathsProbability
Classical probability · form 2
P(Aᶜ) = 1−P(A)
MathsProbability
Classical probability · form 3
0 ≤ P(A) ≤ 1
MathsProbability
Addition rule
P(A∪B) = P(A)+P(B)−P(A∩B)
MathsProbability
Addition rule · form 2
if disjoint: P(A∪B) = P(A)+P(B)
MathsProbability
Addition rule · form 3
P(A∩B) = P(A)+P(B)−P(A∪B)
MathsProbability
Conditional probability
P(A|B) = P(A∩B)/P(B)
MathsProbability
Conditional probability · form 2
P(A∩B) = P(A|B)P(B)
MathsProbability
Conditional probability · form 3
independent: P(A∩B) = P(A)P(B)
MathsProbability
Bayes theorem
P(A|B) = P(B|A)P(A)/P(B)
MathsProbability
Bayes theorem · form 2
P(B) = Σ P(B|Ai)P(Ai)
MathsProbability
Bayes theorem · form 3
odds(A) = P(A)/(1−P(A))
MathsStatistics
Mean and variance
x̄ = Σxi/n
MathsStatistics
Mean and variance · form 2
variance = Σ(xi−x̄)²/n
MathsStatistics
Mean and variance · form 3
standard deviation = √variance