BackPrecalculus Study Guide: Functions, Equations, and Inequalities
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Functions and Their Graphs
Linear, Quadratic, and Absolute Value Functions
Functions are mathematical relationships that assign each input exactly one output. Their graphs provide visual representations of these relationships.
Linear Functions: The general form is , where m is the slope and b is the y-intercept.
Quadratic Functions: The general form is . The graph is a parabola.
Absolute Value Functions: The general form is . The graph is V-shaped.
Transformations: Shifting, stretching, or reflecting graphs by changing parameters.
Example: The graph of is a parabola shifted up by 4 units.
Intercepts and Graph Analysis
Finding x- and y-intercepts
Intercepts are points where the graph crosses the axes.
x-intercept: Set and solve for .
y-intercept: Set and solve for .
Example: For , the y-intercept is and the x-intercept is .
Solving Linear Equations
Methods and Solutions
Linear equations can be solved by isolating the variable.
Standard form:
Solution:
Example: Solve :
Expand:
Add 24:
Divide by 4:
Systems of Equations
Solving for Multiple Variables
Systems of equations involve finding values that satisfy all equations simultaneously.
Substitution and elimination are common methods.
Solutions may be unique, infinite, or nonexistent.
Example: Solve , , :
Set
Formulas and Solving for Variables
Manipulating Formulas
Solving for a specified variable involves algebraic manipulation.
Isolate the desired variable using inverse operations.
Example: Solve for .
Factoring and Expanding Expressions
Products and Standard Form
Factoring and expanding are used to simplify expressions and solve equations.
Product:
Standard form: Expand and combine like terms.
Example:
Rational Expressions
Division and Simplification
Dividing rational expressions involves multiplying by the reciprocal.
Example:
Quadratic Equations
Solving by Formula and Completing the Square
Quadratic equations are solved using the quadratic formula or by completing the square.
Quadratic formula:
Completing the square: Rearranging to form
Example: Solve using the quadratic formula.
Discriminant and Nature of Solutions
Types of Roots
The discriminant determines the nature of the solutions of a quadratic equation.
If : Two distinct real solutions
If : One real solution
If : Two complex solutions
Polynomial Equations and Zero Product Principle
Factoring and Solving
Polynomial equations can be solved by factoring and applying the zero product principle.
Zero product principle: If , then or .
Example: factors to .
Inequalities and Interval Notation
Solving and Graphing
Inequalities are solved similarly to equations, but solutions are expressed as intervals.
Interval notation: for all such that
Graphing: Use number lines to represent solution sets
Example: Solve ; solution is , or .
Absolute Value Inequalities
Solving and Graphing
Absolute value inequalities are solved by considering both positive and negative cases.
General form: leads to
Example: gives
Applications: Word Problems
Translating and Solving
Word problems require translating real-world scenarios into mathematical equations.
Identify variables and relationships
Set up equations and solve
Example: A fax machine charges $2.50 for the first page and nP = 0.65(n - 1) + 2.50$.
Summary Table: Types of Equations and Solution Methods
Equation Type | General Form | Solution Method |
|---|---|---|
Linear | Isolate variable | |
Quadratic | Factoring, quadratic formula, completing the square | |
Polynomial | Factoring, synthetic division | |
Inequality | Isolate variable, interval notation | |
Absolute Value | Split into two inequalities |
Additional info: Some context and explanations have been expanded for clarity and completeness, including general forms and solution steps for equations and inequalities.