MATH 100
Formula Sheet & Notesultra edition · 20 ch + appendices

Ultra edition · worked examples everywhere · appendices

Every formula from Math 100fully expanded, with appendices.

Twenty chapters with at least two worked examples each, pitfall lists, a deep-dive calculus core — then a symbol glossary, a master cram sheet, and the exam playbook.

20chapters + 3 appendices
formula cards
worked examples
pitfall lists

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01

Set Theory

Collections of objects and the algebra of combining them — the language every later chapter is written in.

Foundations
01

Notation & membership

Roster form lists elements; set-builder form describes them: {x : property}.

02

Union & intersection

Union = either; intersection = both. A ∩ B = ∅ means disjoint.

03

Complement & difference

Complement is relative to the universal set U.

04

Subset & equality

Prove A = B by showing A ⊆ B and B ⊆ A.

05

Subset test shortcuts

Three equivalent statements.

06

Inclusion–exclusion (2 sets)

Add sizes, subtract the overlap counted twice.

07

Inclusion–exclusion (3 sets)

Subtract pairwise overlaps, add back the triple.

08

De Morgan's laws

Complement flips ∪ ↔ ∩.

09

Distributive laws

Intersection distributes over union — and vice-versa.

10

Identity & complement laws

∅ is neutral for ∪; U for ∩.

11

Power set

n elements → 2ⁿ subsets, counting ∅ and A itself.

12

Cartesian product

Ordered pairs; in general A × B ≠ B × A. Functions are built from these.

Example 1 · inclusion–exclusion

Class of 40: 25 like algebra, 20 geometry, 8 both. How many like neither?

  1. Neither = 40 − 37.

Answer

Example 2 · power set

List all subsets of {a, b}.

  1. 2² = 4 subsets expected.
  2. ∅, {a}, {b}, {a, b} — count matches.

Answer

Avoid
  • vs : 0 elements vs 1.
  • Reading A ∪ B as “in both” — that's ∩.
  • Writing A ∪ B ∩ C without parentheses.
02

Logic & Reasoning

Statements, implications and quantifiers — the grammar of proof.

Foundations
01

Implication

False only when p true, q false.

02

Contrapositive

Logically identical — often the easiest proof route.

03

Biconditional

“iff” = two proofs.

04

De Morgan (logic)

Push NOT through: AND ↔ OR flips.

05

Negating quantifiers

Swap ∀ ↔ ∃, negate inside.

06

Rules of inference

Affirm the hypothesis; deny the conclusion.

07

Chaining & eliminating

Implications chain; an “or” plus one denial settles the other.

08

Tautology & contradiction

True in every truth-table row, or in none.

Example 1 · negation

Negate: “Every prime greater than 2 is odd.”

  1. Formalize
  2. ∀ → ∃, negate inside.

Answer“There exists a prime > 2 that is not odd.”

Example 2 · contrapositive

Write the contrapositive of “if x² is even, then x is even.”

  1. Negate both parts, reverse direction.

Answer“If x is odd, then x² is odd.” (This is how the theorem is actually proved.)

Avoid
  • Affirming the consequent: p ⇒ q and q do not give p.
  • Negating “all” as “none” — it's “at least one isn't”.
  • Treating converse as equivalent to the original.
03

Number Systems & Absolute Value

ℕ ⊂ ℤ ⊂ ℚ ⊂ ℝ ⊂ ℂ — and the distance function that makes inequalities behave.

Foundations
01

The number ladder

Rationals are ratios p/q; √2, π are irrational.

02

Definition of |x|

Distance from zero — always ≥ 0.

03

Absolute value inequalities

“less thAND”, “greater thOR”.

04

Distance interpretation

|x − a| = distance from x to a.

05

Triangle inequality

A shortcut never beats both sides added.

06

Inequality rules

Multiply by negative → reverse the sign.

07

Laws of exponents

Fractional = root + power; negative = reciprocal.

08

Radical rules

The last one needs the absolute value.

09

Interval notation

Round = excluded; square = included.

Example 1 · |inequality|

Solve

  1. Add 1, divide by 2.

Answer

Example 2 · surds

Simplify

Answer

Avoid
  • Forgetting to flip the sign when multiplying by a negative.
  • Writing |a + b| = |a| + |b|.
  • Dropping the absolute value in .
04

Complex / Imaginary Numbers

Adjoining √(−1) — every polynomial gets roots, and rotation becomes multiplication.

Number systems
01

The imaginary unit

Powers cycle: 1, i, −1, −i.

02

Standard form

Point (a, b) in the Argand plane.

03

Conjugate & modulus

Conjugate reflects across the real axis.

04

Multiplication

FOIL, then i² → −1.

05

Division

Multiply top and bottom by the conjugate of the denominator.

06

Modulus & conjugate rules

Modulus respects products.

07

Polar form

r = |z|, tan θ = b/a (fix quadrant). Multiplying = scale + rotate.

08

Euler's formula

The exponential unifies trigonometry.

09

De Moivre's theorem

Modulus to the n, argument times n.

10

n-th roots

A regular n-gon on a circle of radius ⁿ√r.

11

Complex roots of quadratics

Δ < 0 → conjugate pair.

Example 1 · De Moivre

Compute

Answer

Example 2 · division

Simplify

  1. × conjugate:
  2. Numerator:

Answer

Avoid
  • Losing the sign when replacing i² by −1.
  • Writing |a + bi| = a + b.
  • Dividing without the conjugate trick.
05

Functions & Transformations

One output per input — composing, inverting, sliding and stretching graphs.

Algebra
01

Composition

Inside-out. In general f ∘ g ≠ g ∘ f.

02

Inverse function

Graphs mirror across y = x; only one-to-one functions invert.

03

General transformation

h right, k up, |a| vertical stretch, b compresses horizontally by 1/b.

04

Even & odd

cos, x² even; sin, tan, x³ odd.

05

Average rate of change

Secant slope — the warm-up for the derivative.

06

Difference quotient

Let h → 0 and this becomes f′(x).

07

Function library — domains & ranges

f(x)
domain
range

Every graph this semester is a transformation of these six parents.

08

Line tests

Vertical test → function? Horizontal test → invertible?

One y per x; one x per y.

09

Inverse recipe

  1. Write y = f(x).
  2. Swap x and y.
  3. Solve for y.
  4. Restrict domain first if needed.

Verify with f(f⁻¹(x)) = x.

Example 1 · composition

: find (g ∘ f)(x) and its domain.

  1. ; need — always.

Answer, domain

Example 2 · inverse

Find the inverse of

  1. Swap:
  2. Solve:

Answer

Avoid
  • Reading f⁻¹ as a reciprocal.
  • Wrong transformation order — inside shifts apply before outside scaling.
  • Writing √(x² + 1) = x + 1.
06

Polynomials & Roots

Where polynomials cross the axis, and what the coefficients whisper about those crossings.

Algebra
01

Quadratic formula

Works every time.

02

Discriminant

Reads the roots before you solve.

03

Vieta's relations

Cubic: α+β+γ = −b/a, αβγ = −d/a.

04

Factor & remainder theorems

Division by (x − a) leaves remainder f(a).

05

Vertex

Axis of symmetry x = h.

06

Rational root theorem

Factors of the constant over factors of the leading coefficient.

07

Factoring identities

Difference of squares; sum/difference of cubes.

08

Quadratic inequalities

Sketch: a > 0 smiles, a < 0 frowns.

09

Fundamental theorem of algebra

Degree n ⟹ exactly n complex roots, counting multiplicity.

Why complex numbers exist.

Example 1 · cubic by trial

Solve

  1. x = 2 works: 8 − 16 + 2 + 6 = 0 ✓
  2. Divide:

Answer

Example 2 · discriminant

For what k does have a double root?

  1. Double root ⟺ Δ = 0:

Answer (root x = −2)

Avoid
  • Dropping the ± in the quadratic formula.
  • Forgetting multiplicity when counting roots.
  • Vieta sign slips: sum = −b/a.
07

Exponentials & Logarithms

Inverse operations: exponents grow, logarithms ask “to what power?”

Algebra
01

Definition

A logarithm is an exponent in disguise. Domain x > 0.

02

Laws of logs

Multiplication becomes addition.

03

Change of base

Any base via ln or log₁₀.

04

Cancellation

Inverses undo each other — the key solving move.

05

The number e

The base that grows at its own rate.

06

Growth & decay

Discrete vs continuous compounding.

07

Doubling & half-life

Set A = 2P or P/2 and solve.

08

Solving exponentials

Isolate the exponential, then log both sides.

Example 1 · exponential equation

Solve

  1. ln:

Answer

Example 2 · log equation

Solve

  1. Combine:
  2. ; reject −2 (domain).

Answer

Avoid
  • Splitting .
  • Logging only one side of an equation.
  • Mixing ln with log₁₀.
08

Sequences & Series

Patterns indexed by n — adding them up, sometimes forever.

Algebra
01

AP n-th term

Constant step d.

02

AP sum

Gauss: pair first with last.

03

GP n-th term

Constant ratio r.

04

GP sum

r = 1 gives Sₙ = n·a₁.

05

Infinite GP

Converges only for |r| < 1.

06

Famous sums

Σc = nc; constants factor out.

07

Means

Always G.M. ≤ A.M.

08

Repeating decimals

Every repeating decimal is a GP.

Example 1 · AP

a₃ = 7, a₈ = 22. Find S₁₀.

  1. ; ;

Answer

Example 2 · infinite GP

Sum

  1. — |r| < 1 ✓

Answer

Avoid
  • AP formula on a GP (or vice versa).
  • Writing aₙ = a₁ + nd.
  • Using when |r| ≥ 1.
09

Binomial Theorem

Expanding (a + b)ⁿ without multiplying n times.

Algebra
01

The theorem

Exponents in each term add to n.

02

General term

Grab any single term without expanding.

03

Pascal identities

Symmetry and the triangle rule.

04

Counting the expansion

Set a = b = 1 for the 2ⁿ sum.

05

Even / odd coefficient sums

Set a = 1, b = −1: the two halves are equal, each 2ⁿ⁻¹.

06

Middle terms

Parity of n decides.

07

Strategy: specific terms

For “the term in ”: write the general term, match powers, solve for k.

Never expand the whole thing.

Example 1 · a coefficient

Coefficient of x² in

  1. :

Answer

Example 2 · middle term

Find the middle term of

  1. n = 6 even → T₄, i.e. k = 3.

Answer — it's also the term independent of x.

Avoid
  • Dropping the sign of the second term.
  • Confusing term number with k (Tk+1, k from 0).
  • Writing (a + b)² = a² + b².
10

Permutations & Combinations

Counting arrangements — the whole chapter turns on: does order matter?

Counting
01

Factorial

Ways to order n distinct objects.

02

Multiplication principle

Count slot by slot, multiply.

03

Permutations

Order matters: podiums, passwords.

04

Combinations

Order doesn't: committees, card hands.

05

The link

Each group hides r! orderings.

06

Repeats: multinomial

Divide by each run of identical items.

07

Circular arrangements

Pin one person, arrange the rest.

08

Restrictions

Glue for “together”; complement for “apart”.

09

Complement principle

The universal shortcut for “at least” questions.

Example 1 · repeats

Arrangements of BANANA?

  1. 3 A's, 2 N's, 1 B:

Answer

Example 2 · committee

Choose a 3-person committee from 8 people.

  1. Order irrelevant → C:

Answer

Avoid
  • P where order is irrelevant (or C where it matters).
  • Treating identical items as distinct.
  • Double-counting circular arrangements.
11

Trigonometric Functions

Angles, the unit circle, and the six functions that turn geometry into algebra.

Trigonometry
01

SOH · CAH · TOA

Right-triangle definitions.

02

Unit circle

Extends trig to every angle.

03

Radians

Arc length and sector area need radians.

04

Reciprocals

csc↔sin, sec↔cos, cot↔tan.

05

Periods

For y = sin(bx) the period becomes 2π/b; tan gives π/b.

06

Sinusoid form

Amplitude |a|, period 2π/b, shift c, midline d.

07

Reference angles

Reduce to Q1, fix the sign with ASTC.

08

Inverse trig ranges

Principal values only.

09

Signs — ASTC

All · Sin · Tan · Cos

Positive functions in quadrants I–IV.

10

Special angle values

θ30°45°60°90°
sin θ
cos θ
tan θundef.

Memorize it — it powers half of Ch 12 and the calculus trig work.

Example 1 · equation

Solve on

  1. Reference angle ; sin positive in Q1, Q2.

Answer

Example 2 · reference angle

Find cos 120° exactly.

  1. Reference angle 60°; Q2 → cos negative.

Answer

Avoid
  • Stopping at the first solution of a trig equation.
  • Assuming arcsin(sin x) = x outside the principal range.
  • Mixing degrees and radians in one equation.
12

Trigonometric Identities & Equations

Rewriting trig into the form the problem demands — and solving non-right triangles.

Trigonometry
01

Pythagorean identities

One identity, three disguises.

02

Even–odd

sin, tan odd; cos even.

03

Sum & difference

Cosine flips the sign.

04

Double angle

Pick the form that cancels.

05

Power-reducing

Squared trig → linear in cos 2θ. Essential for Ch 19.

06

Product-to-sum

Products become integrable sums.

07

Sum-to-product

Great for factoring equations.

08

Auxiliary angle form

One sinusoid; extrema ±R.

09

Sine & cosine rules

Sine rule: opposite pairs. Cosine rule: SAS or SSS.

10

Triangle area

Two sides + included angle.

Example 1 · auxiliary form

Write as R sin(θ + α); state the max.

  1. ;

Answer, max 5

Example 2 · equation, 4 solutions

Solve on

  1. All four quadrants contribute.

Answer

Avoid
  • Cosine-sum sign: takes a minus.
  • Dividing away sin θ and losing solutions.
  • Squaring both sides without checking for extraneous roots.
13

Vectors

Magnitude and direction — plus two very different ways to multiply.

Geometry
01

Components & magnitude

Pythagoras in 2D/3D.

02

Operations & unit vectors

Componentwise; normalize to length 1.

03

Dot product

Result is a scalar.

04

Angles & perpendicularity

Dot > 0 acute, = 0 right, < 0 obtuse.

05

Projections

One is a vector, one is a length.

06

Cross product magnitude

In 2D: |u₁v₂ − u₂v₁|. Half of it is the triangle area.

07

Work

Only the along-motion component counts.

Example 1 · angle

: dot product and angle.

Answer

Example 2 · triangle area

Area of the triangle spanned by

  1. 2D cross magnitude:
  2. Triangle = half the parallelogram.

Answer

Avoid
  • Forgetting the square root in |v|.
  • Dot product when the question asks an area.
  • Skipping normalization in .
14

Matrices & Determinants

Arrays encoding linear systems — with one surprise: multiplication doesn't commute.

Linear algebra
01

Matrix multiplication

Row of A · column of B; inner dims match.

02

The big warning

In general AB ≠ BA, and AB = 0 doesn't force A = 0 or B = 0.

Never divide by a matrix.

03

Determinant 2×2

Main diagonal minus anti-diagonal.

04

Inverse 2×2

Swap diagonal, flip the rest, divide by det.

05

Identity & singularity

Also — order reverses.

06

Transpose rules

Transpose also reverses order.

07

Row ops & det

Determinant behavior under elimination.

08

Cramer's rule

Replace column with constants, det, divide.

09

Matrix equations

det = 0 → none or infinitely many solutions.

Example 1 · solve with A⁻¹

Solve

Answer

Example 2 · AB ≠ BA, live

: compute AB and BA.

  1. (columns of A swapped)
  2. (rows of A swapped)

AnswerAB ≠ BA — order matters, concretely.

Avoid
  • Assuming AB = BA.
  • Order slips in and .
  • det = ad + bc — it's ad − bc.
15

Lines, Circles & Conics

Equations as pictures: slopes, distances, and the curves from slicing a cone.

Geometry
01

Slope

Vertical: undefined; horizontal: 0.

02

Forms of a line

Point-slope, slope-intercept, general.

03

Parallel & perpendicular

Negative reciprocals.

04

Distance & midpoint

Pythagoras; averaging coordinates.

05

Point-to-line distance

Shortest distance from (x₀, y₀) to Ax + By + C = 0 — the tangency test for circles.

06

Circle

Center (h, k); signs flip when reading off.

07

Conic standard forms

+ → ellipse, − → hyperbola, one square → parabola.

08

Focus, directrix, asymptotes

Conics are focus–directrix distance ratios (eccentricity).

09

Perpendicular bisector

The standard move for finding circle centers.

Example 1 · complete the square

Center & radius of

Answercenter (3, −2), r = 5

Example 2 · perpendicular bisector

Bisector of the segment from (1, 2) to (5, 6)?

  1. Midpoint (3, 4); segment slope → perp slope −1.

Answer

Avoid
  • Un-flipped center signs: (x − 3)² means h = +3.
  • Plugging a slope in for a vertical line.
  • Forgetting the √ after computing d².
Part · Calculus — deep dive

Chapters 16–19, blown wide open

ε–δ foundations, discontinuity taxonomy, asymptote recipes, logarithmic & implicit differentiation, a complete derivative table, curve-sketching protocol, Riemann sums, substitution with changed limits — and fourteen worked examples.

16

Limits & Continuity

The doorway to calculus: what a function approaches — even where it isn't defined.

Calculus · deep dive
01

Limit laws

Limits pass through +, −, ×, ÷.

02

Famous limit #1

Radians; for small x, sin x ≈ x.

03

Famous limit #2

Multiply by (1 + cos x) first.

04

Famous limits: exp & log

eˣ ≈ 1 + x and ln(1 + x) ≈ x, made rigorous.

05

The number e

Compound interest pushed to continuous.

06

ε–δ definition

Within ε of L by staying within δ of a.

07

Continuity at a point

Fail any one and the graph breaks.

08

Types of discontinuity

  1. Removable — limit exists; f(a) missing/wrong (a hole).
  2. Jump — one-sided limits exist but differ.
  3. Infinite — blow-up (vertical asymptote).

Classify before describing.

09

One-sided & infinite

Both sides must agree; blow-up → vertical asymptote.

10

Limits at ∞ (rationals)

Degree showdown → horizontal asymptote.

11

Asymptote recipe

  1. Vertical: zeros of denominator where numerator ≠ 0.
  2. Horizontal: degree showdown.
  3. Slant: deg N = deg D + 1 — long-divide.

Check both sides of every vertical candidate.

12

Squeeze theorem

Standard for oscillating factors like sin(1/x).

13

Factor-then-substitute

0/0 means factor and cancel.

Example 1 · factoring

  1. 0/0 →

Answer (removable hole)

Example 2 · conjugate

  1. × conjugate:

Answer

Example 3 · continuity

Find k so is continuous at 1.

  1. Left limit 2; right value k — match them.

Answer

Avoid
  • Declaring “undefined” on 0/0 — factor instead.
  • Calling ∞ a value; one-sided signs can disagree.
  • only at x → 0.
  • Cancelling across sums: .
  • Forgetting continuity needs all three conditions.
17

Differentiation Rules

One limit definition, a complete toolbox of rules, and four techniques for every shape of function.

Calculus · deep dive
01

Definition

Tangent slope as the secant tightens.

02

Power rule

Any real n — negatives and fractions included.

03

Linearity

Term by term; constants die.

04

Product rule

E.g. .

05

Quotient rule

low·D-high − high·D-low, over low².

06

Chain rule

Outside-in; multiply by the inner derivative.

07

Trig derivatives

Co-functions carry a minus.

08

Exp & log derivatives

e^x equals its own derivative.

09

Inverse trig derivatives

arccos is the negative twin.

10

Implicit differentiation

Each y-term picks up a dy/dx; collect and solve.

11

Logarithmic differentiation

  1. Take ln of both sides.
  2. Differentiate:
  3. Solve for y′; substitute y back.

The weapon for xˣ and product towers.

12

Derivative of an inverse

Reciprocal slope at the mirrored point.

13

Differentials

Powers substitution in Ch 19.

14

Master derivative table

f(x)f′(x)f(x)f′(x)

Everything else is this table plus product, quotient and chain.

Example 1 · chain

Differentiate

  1. Outside × inside .

Answer

Example 2 · logarithmic

Differentiate

Answer

Example 3 · implicit

Slope of at (1, 2).

Answer

Avoid
  • Missing inner derivatives: .
  • — the 3 belongs in front.
  • Product vs chain mix-ups: x·sin x = product; sin(x²) = chain.
  • , not 5.
  • Dropping the minus in and .
18

Applications of Derivatives

Tangents, motion, extrema, concavity — plus related rates and optimization.

Calculus · deep dive
01

Tangent line

Normal line: slope −1/f′(a).

02

Motion

Speeding up ⟺ v, a same sign.

03

Increase / decrease

Sign of f′ = direction of the graph.

04

Critical points

Extrema can only occur here.

05

First derivative test

Sign chart of f′ — always reliable.

06

Second derivative test

f″(c) = 0 → test silent; use the sign chart.

07

Concavity & inflection

Inflection = f″ changes sign.

08

Closed-interval method

Global extrema live among these values.

09

Mean Value Theorem

Rolle: f(a) = f(b) ⟹ f′(c) = 0.

10

L'Hôpital's rule

Confirm the form first; repeatable.

11

Linear approximation & error

Tangent as estimator; differential as error propagator.

12

Related rates — method

  1. Draw it; label changing quantities.
  2. Link them with a geometric equation.
  3. Differentiate wrt t.
  4. Substitute after differentiating.

Every time-varying variable earns a d/dt term.

13

Curve-sketching checklist

  1. Domain, intercepts, symmetry.
  2. Asymptotes (Ch 16 recipe).
  3. f′ sign chart → extrema.
  4. f″ sign chart → concavity.
  5. Plot key points; sketch.

Run in order — each step narrows the picture.

Example 1 · optimization

100 m fencing, three sides (barn is the fourth). Maximize area.

  1. ;
  2. ;

Answer

Example 2 · related rates

Ripple expands at dr/dt = 2 m/s. dA/dt when r = 5?

Answer

Example 3 · L'Hôpital twice

  1. 0/0 → , still 0/0 →

Answer

Example 4 · linear approximation

Estimate by hand.

Answer

Avoid
  • Skipping endpoints on closed intervals.
  • L'Hôpital before verifying 0/0 or ∞/∞.
  • “Critical point” ≠ “extremum” (y = x³ at 0).
  • Substituting numbers before differentiating in related rates.
  • Reading concavity from f′ instead of f″.
19

Integration

Differentiation run backwards — and, via the Fundamental Theorem, exact areas.

Calculus · deep dive
01

Definition (Riemann)

Area as the limit of finer rectangles.

02

Power rule (reverse)

n = −1 is the log case.

03

Basic antiderivatives

Ch 17's table read right-to-left.

04

More trig integrals

sin²/cos²: power-reduce first.

05

Reverse chain-rule patterns

IntegralAntiderivativeIntegralAntiderivative

Linear inside? Divide by its slope a. The pattern behind u-substitution.

06

Linearity

Split sums, pull out constants.

07

FTC, Part 2

Definite integral = antiderivative at the ends.

08

FTC, Part 1

Upper limit g(x) → chain: f(g(x))·g′(x). Exam favorite.

09

Integral properties

Splitting and reversing intervals.

10

u-substitution

Chain rule in reverse.

11

Substitution with limits

Change bounds with the variable — no back-substitution.

12

Area between curves

Top minus bottom; intersections give the bounds.

13

Average value

Some c satisfies f(c) = f_avg (MVT for integrals).

14

Which technique?

  1. Power / table / linear inside → integrate directly.
  2. Inside function and its derivative present → u-sub.
  3. Trig powers/products → identities first.
  4. Ugly back-substitution? Change the limits instead.

Scan for the derivative of the inside — the #1 tell.

Example 1 · FTC

Answer

Example 2 · u-sub with limits

  1. ; bounds

Answer

Example 3 · area between curves

Area enclosed by and .

  1. Meet at 0, 1; line on top.

Answer

Example 4 · FTC + chain

Differentiate

  1. Upper limit x² → chain:

Answer

Avoid
  • Forgetting + C on indefinite integrals.
  • , not +cos x.
  • Missing reverse-chain factors: .
  • Keeping x-bounds after switching to u.
  • Quoting signed area as “the area”.
20

Probability & Statistics

Quantifying chance and summarizing data — where Ch 1's sets get measured.

Data
01

Classical probability

Equally likely outcomes assumed.

02

Complement

“At least one” = 1 − P(none).

03

Addition rule

Mutually exclusive → just add.

04

Conditional

Sample space shrinks to B.

05

Independence

No influence ⇔ multiply.

06

Total probability

Bayes' denominator machinery.

07

Bayes' theorem

Update belief with evidence; P(A|B) ≠ P(B|A).

08

Binomial distribution

k successes in n independent trials.

09

Binomial mean & variance

Expected successes = n·p.

10

Mean, variance, σ

σ in the data's units; σ² is not.

11

Expected value & z-score

Long-run average; σ's from the mean.

Example 1 · dice

Two fair dice: P(sum = 7)?

  1. 36 outcomes; 6 favorable.

Answer

Example 2 · binomial

5 fair coin flips: P(exactly 3 heads)?

Answer

Avoid
  • The gambler's fallacy.
  • Swapping P(A|B) with P(B|A).
  • Adding probabilities of overlapping events without subtracting.
Appendices

The last-mile reference

A glossary of every symbol on this sheet, a 24-formula cram grid for the night before, and a playbook for the exam room itself.

A1

Symbol Glossary

Every mark you've met this semester, in one table — read it aloud column by column and the course sounds like a sentence.

Appendix

Notation dictionary

SymbolNameHow to read it
element ofx ∈ A — “x belongs to A”
not element ofy ∉ A — “y is not in A”
subsetA ⊆ B — every element of A is in B
unionin A or B (or both)
intersectionin both A and B
empty setthe set with no elements
power setthe set of all subsets of A
Cartesian productA × B — all ordered pairs (a, b)
for all∀x — “for every x”
there exists∃x — “at least one x”
negation¬p — “not p”
conjunctionp ∧ q — “p and q”
disjunctionp ∨ q — “p or q (or both)”
impliesp ⇒ q — “if p then q”
iffp ⇔ q — “p if and only if q”
absolute value / modulus / sizedistance from 0; |z|; |A| = number of elements; a | b = divides
square rootthe non-negative number whose square is x
infinityunbounded growth — not a number
constantsπ ≈ 3.14159; e ≈ 2.71828
number setsnaturals · integers · rationals · reals · complex
summationΣ aₖ — add the terms as k runs its range
integral∫ f dx — signed area / antiderivative
limitthe value f approaches as x approaches a
derivativeinstantaneous rate of change of f
approximately≈ — close to, not exactly
perpendicularmeeting at 90°; u ⊥ v ⟺ u·v = 0
change / discriminantΔy = change in y; Δ = b² − 4ac
mean, std deviationcenter and spread of data
probabilitychance of A; chance of A given B

If a symbol on an exam question stops you cold, find it here first — notation is half the subject.

A2

Master Cram Sheet

The twenty-four formulas most likely to appear, anywhere, in any form. If you know these cold, you can rebuild the rest.

Appendix
06 quadratic formula
06 discriminant
07 log laws
07 change of base
04 imaginary unit
04 modulus
04 De Moivre
08 infinite GP
09 binomial theorem
10 permutations
10 combinations
12 Pythagoras trig
12 cosine rule
16 famous limit
17 definition
17 power rule
17 product rule
17 quotient rule
17 chain rule
18 tangent line
18 MVT
19 power rule ∫
19 FTC
20 Bayes
A3

Exam Playbook

The non-mathematical skills that decide 10–15% of the grade: how to run the paper, and how to check the answers.

Appendix
During the exam
  1. Scan the whole paper first; do the sure-thing questions first to bank marks.
  2. Write the formula before substituting numbers — it earns method marks even if arithmetic slips.
  3. Show every step; partial credit is real and generous.
  4. Check units and modes: radians vs degrees, cm vs m.
  5. Stuck for 3+ minutes? Mark it, move on, return later.
  6. Sketch graphs — a picture often earns the mark algebra can't.
  7. Re-read what was actually asked: slope vs equation, area vs integral, exact vs decimal.
  8. Don't scribble out mistakes — one clean line through them keeps working legible.
The checking pass
  1. Substitute roots back into the original equation.
  2. Check domains — reject extraneous log/root answers.
  3. Indefinite integral? Confirm + C is present.
  4. Sanity checks: area > 0, 0 ≤ P ≤ 1, probabilities sum to 1.
  5. Final 5 minutes: sweep for unanswered questions — something beats nothing.