College Algebra
College7 units and 53 lessons. Helio talks each one through and draws each step on a board.
Units
Algebraic expressions
7 lessons- Exponent rules, radicals and rational exponents; sums and products of rational and irrational numbersSimplify expressions with exponents and radicals, then justify whether exact results are rational or irrational.
- Adding, subtracting and multiplying polynomialsAdd, subtract and multiply polynomials; use special products and identify a product’s degree.
- Factoring out the GCF and factoring x^2 + bx + cFactor a quadratic completely by taking out the greatest common factor, then finding the pair with the right product and sum, and read the zeros from the factors.
- Factoring ax^2 + bx + c by groupingFactor a trinomial whose x² term has a coefficient by splitting the middle term with the product ac, grouping, and checking by multiplying back.
- Special products: difference of squares and perfect square trinomialsSpot a difference of squares or a perfect square trinomial, factor it without a search, and factor completely when a common factor or a repeated pattern is hiding.
- Rational exponents and radicalsEvaluate rational powers, combine them using exponent laws, and simplify radicals.
- Rewriting rational expressions: simplify, divide, add and multiplyRewrite rational expressions in four ways while keeping every original denominator restriction.
Equations and inequalities
13 lessons- Solving as reasoning: justifying each stepSolve linear equations, justify each line, and check solutions in the original equation.
- Solving multistep linear equations, including special casesSolve multistep equations and distinguish one solution, no solution, and every real number as a solution.
- Rearranging formulas to highlight a quantityRearrange a formula to leave a requested variable alone, including when it appears in two terms.
- Solving and graphing linear inequalities, including compound inequalitiesSolve and graph single and compound inequalities, including reversing signs when dividing by a negative.
- Absolute value equations and inequalitiesSolve absolute value equations and inequalities, graph solutions, and check candidates in the original statement.
- Solving quadratic equations by factoringSolve a quadratic equation by making one side zero, factoring, and checking every solution.
- Completing the square to reveal the vertex and solveRewrite a quadratic to find its vertex, then complete the square to solve an equation.
- The quadratic formula and the discriminantSolve quadratics with the formula and predict the number of real solutions from the discriminant.
- Choosing a method to solve a quadraticChoose an efficient method, solve exactly when possible, and check which solutions fit the question.
- Solving radical equations and spotting extraneous solutionsSolve square-root equations and check every candidate in the original equation.
- Solving rational equationsSolve rational equations by clearing denominators, then reject answers that make an original denominator zero.
- The number i and arithmetic with complex numbersSimplify complex-number sums, products, powers of i, and quotients into a + bi form.
- Complex solutions of quadratic equationsSolve quadratics with non-real roots and connect those roots to graphs and factors.
Functions and graphs
11 lessons- What a function is: one output per input, function notation, domain and rangeTest whether a relation is a function, read function notation, and find domain and range in context.
- Interpreting key features of graphs and tables in contextInterpret graph and table features with input and output units, then sketch a graph from a story.
- Average rate of change over an intervalFind and interpret average rates from graphs, tables, and formulas, with appropriate units.
- Slope-intercept form: graphing and writing linesGraph a line from y = mx + b, write y = mx + b from a graph, a point and slope, or two points, and say what m and b mean in a story.
- Point-slope and standard form; converting between forms; horizontal and vertical linesWrite a line in point-slope form from one point and a slope, graph from standard form using intercepts, convert between all three forms, and choose the form the information suggests.
- Graphing quadratic functions: vertex, axis of symmetry and interceptsSketch a parabola from its opening, axis, vertex, intercepts and mirror points, and say what its minimum or maximum value is.
- Vertex form and maximum/minimum problemsRead the vertex from y = a(x − h)² + k, rewrite a quadratic into that form, and use it to find the best input and the best value in a situation.
- Graphing square root, cube root, absolute value, piecewise and step functionsLocate familiar graph shapes, move them, and draw only the parts allowed by each input rule.
- Transformations across function familiesMove, stretch and reflect any parent function, track its key points and features, read a transformation from a formula, and test for even and odd symmetry.
- Building functions by combining: sums, products, quotients and compositionBuild and evaluate function combinations, compare composition orders, and find allowed inputs.
- Inverse functions: finding, graphing and restricting the domainDecide whether a function can be undone, find its inverse by swapping and solving, and restrict the domain when it cannot.
Polynomial and rational functions
7 lessons- Seeing structure: factoring higher-degree polynomials by patternFactor higher-degree polynomials completely by spotting chunks, choosing a pattern, and checking every factor.
- Polynomial arithmetic, closure and proving identitiesMultiply polynomials, prove an identity, generate Pythagorean triples, and explain closure.
- Polynomial division, the Remainder Theorem and the Factor TheoremDivide polynomials, find remainders by substitution, and decide when a linear expression is a factor.
- Zeros, multiplicity and end behavior: sketching polynomial graphsSketch a polynomial using its zeros, crossings or touches, end behavior, and y-intercept.
- The Fundamental Theorem of Algebra and complex zeros of polynomialsFind and count complex zeros, identify real x-intercepts, and build real polynomials from zeros.
- Graphing rational functions: asymptotes, holes and interceptsSketch a rational graph from its holes, asymptotes, intercepts, and behavior near a vertical asymptote.
- Polynomial and rational inequalities with sign chartsSolve polynomial and rational inequalities by marking boundaries, testing signs, and choosing endpoints correctly.
Exponential and logarithmic functions
5 lessons- Exponential growth and decay models, e and continuous growthChoose an exponential model, then calculate an amount from a given time.
- Logarithms as exponentsRewrite logarithms as powers, evaluate them, use log and ln, and identify invalid inputs.
- Properties of logarithmsExpand, condense, and evaluate logarithms using the product, quotient, power, and change-of-base properties.
- Solving exponential and logarithmic equationsSolve exponential and logarithmic equations, give exact log answers and calculator approximations, and check log inputs.
- Exponential and logarithmic functions as inverses: graphs and featuresGraph an exponential–logarithmic inverse pair, identify its features, and find an inverse after a shift.
Systems of equations
6 lessons- Systems of linear equations: solutions as intersectionsFind and check a shared point, then predict how many solutions two lines have.
- Solving systems by substitutionSolve a system by substitution, check its ordered pair, and recognize no solution or infinitely many solutions.
- Solving systems by elimination, and why it worksSolve systems by elimination and explain why scaling and reversible combinations preserve their solutions.
- Systems of a linear and a quadratic equationFind and check every point shared by a line and a parabola; use the same substitution idea with a circle.
- Modelling with systems and choosing a methodModel two facts with a system, choose a solution method, and check the answer in context.
- Graphing linear inequalities and systems of inequalities as half-planesGraph each inequality and identify the points that satisfy every rule in a system.
Sequences and series
4 lessons- Arithmetic and geometric sequences: recursive and explicit rules, and finite geometric seriesWrite recursive and explicit rules, find a distant term, and sum a finite geometric series.
- Sigma notation and finite arithmetic and geometric seriesEvaluate finite sums in sigma notation and use a geometric sum to find a loan payment.
- Infinite geometric series and convergenceDecide whether an infinite geometric series has a finite sum, and find that sum for decimals and rebound distances.
- The Binomial Theorem and Pascal's triangleUse Pascal's triangle to expand a binomial or find a specified term.
