Overview
This lecture provided a comprehensive review of Algebra 2 topics relevant for the Regents exam, including test format, core content areas (number systems, functions, algebra, trigonometry, statistics, and probability), and essential definitions, formulas, and strategies.
Regents Exam Format
- Four main units: Number & Quantity (5–12%), Algebra (35–44%), Functions (30–40%), Statistics & Probability (14–21%).
- 3 hours, 37 questions: 24 multiple choice (2 pts each), 8 short answer (2 pts each), 4 extended response (4 pts each), 1 final question (6 pts).
- Raw scores converted to scaled scores; about 33% correct needed to pass.
Number & Quantity
- Real numbers: rational (includes natural, whole, integers) and irrational (non-terminating, non-repeating).
- Rationalizing denominators: multiply by conjugate to eliminate square roots.
- Polynomial division: similar to long division; if remainder is zero, divisor is a factor.
- Complex numbers: i = √(-1); complex numbers are in form a + bi.
Functions
- A function passes the vertical line test: one y-value per x-value.
- Domain: input values where function is defined; for rational, exclude values making denominator zero; for radicals, radicand ≥ 0.
- Range: all possible output (y) values.
- 1:1 functions: pass both vertical/horizontal line tests; onto: every y-value covered.
- Compositions: f(g(x)); plug one function into another.
- Inverses: swap x and y, solve for y.
Function Characteristics
- End behavior: determined by highest degree and leading coefficient.
- Multiplicity: number of times a factor repeats affects graph behavior.
- Transformations: Horizontal (inside parentheses: shifts, stretches, reflections over y-axis), Vertical (outside: shifts, stretches, reflections over x-axis).
- Remember: H.I.Y.A. “Horizontal Inside Y-axis”; V.X.V. “Vertical X-axis Vertical Outside”.
Algebra: Linear, Quadratic, Sequences
- Slope: (y₂-y₁)/(x₂-x₁), rise over run.
- Linear equations: y = mx + b (slope and y-intercept).
- Three-variable systems: use elimination method; organize, eliminate variables step by step.
- Quadratics: y = ax²+bx+c; use quadratic formula, axis of symmetry is -b/2a, discriminant decides number/type of roots.
- Focus/directrix of parabolas: vertex form y = (x-h)²/(4p) + k; focus at (h, k+p), directrix at y = k-p.
- Sequences: arithmetic (add/subtract) and geometric (multiply/divide); explicit vs. recursive formulas.
Trigonometry
- Radians ↔ degrees: deg × π/180 = rad; rad × 180/π = deg.
- Primary trig functions: sin (opposite/hypotenuse), cos (adjacent/hypotenuse), tan (opposite/adjacent).
- Special triangles: memorize exact sin/cos/tan for 30°, 45°, 60°.
- Unit circle: connects trig functions to (x, y) coordinates.
- Inverse trig: arcsin, arccos, arctan to find angles.
- Trig graphs: y = A sin(B(x–C)) + D; amplitude A, period 2π/B, phase shift C, vertical shift D.
Statistics & Probability
- Study types: sample surveys, observational studies, controlled experiments; single/double blind.
- Normal distribution: 68% within 1σ, 95% within 2σ, 99.7% within 3σ of mean.
- Confidence intervals: mean ± z·(σ/√n); memorize z-values for 90%, 95%, 99% confidence.
- Probability: P(A∪B) = P(A) + P(B) – P(A∩B); complements: P(not A) = 1 – P(A); independent/mutually exclusive events; conditional probability.
Key Terms & Definitions
- Rational Number — A number that can be written as a fraction or repeating/terminating decimal.
- Irrational Number — A non-repeating, non-terminating decimal (e.g., π, √2).
- Amplitude — Half the distance between maximum and minimum y-values in a trig graph.
- Frequency/Period — Frequency: cycles per unit; Period: length of one cycle (2π/frequency).
- Quadratic Formula — x = [-b ± √(b²-4ac)]/(2a).
- Discriminant — b² - 4ac; determines type and number of quadratic roots.
- Standard Deviation (σ, s) — Measure of data spread around the mean.
- Confidence Interval — Range estimating a population parameter, based on sample data.
Action Items / Next Steps
- Memorize core formulas, properties, and z-values for confidence intervals.
- Practice function transformations and trig identities.
- Review calculator functions for regression and statistics (normCDF, LinSolve, sigma notation).
- Complete recommended practice problems and review notes for each unit.