IndietroCollege Algebra: Review and Foundations Study Notes
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Review of Fundamental Algebraic Concepts
Scientific Notation
Scientific notation is a method of expressing very large or very small numbers in the form a × 10n, where 1 ≤ |a| < 10 and n is an integer.
Purpose: Simplifies calculations and representation of numbers in science and engineering.
Standard Form:
Example: 0.00056 =
Operations:
Multiplication: Multiply the coefficients and add the exponents:
Division: Divide the coefficients and subtract the exponents:
Addition, Subtraction, and Multiplication of Polynomials
Polynomials are algebraic expressions consisting of variables and coefficients, combined using addition, subtraction, and multiplication.
Addition/Subtraction: Combine like terms (terms with the same variable and exponent).
Multiplication: Use the distributive property to multiply each term in one polynomial by each term in the other.
Example:
Example:
Factoring Polynomials
Factoring is the process of writing a polynomial as a product of its factors.
Common Methods:
Greatest Common Factor (GCF): Factor out the largest common factor from all terms.
Factoring Trinomials: Express as where and for .
Difference of Squares:
Example:
Multiplication and Division of Rational Expressions
Rational expressions are fractions where the numerator and/or denominator are polynomials.
Multiplication: Multiply numerators and denominators, then simplify.
Division: Multiply by the reciprocal of the divisor.
Example:
Example:
Addition and Subtraction of Rational Expressions
To add or subtract rational expressions, first find a common denominator.
Steps:
Factor denominators if possible.
Find the least common denominator (LCD).
Rewrite each expression with the LCD.
Add or subtract numerators, keep the common denominator.
Simplify if possible.
Example:
Equations and Inequalities
Solving Linear Equations
Linear equations are equations of the first degree (the highest exponent of the variable is 1).
Standard Form:
Solution:
Example:
Solving Quadratic Equations by Factoring
Quadratic equations are equations of the form .
Factoring: Express the quadratic as a product of two binomials and set each factor to zero.
Example:
Using the Quadratic Formula
The quadratic formula provides the solutions to any quadratic equation .
Formula:
Discriminant: determines the nature of the roots (real and distinct, real and equal, or complex).
Example:
Addition, Subtraction, and Multiplication of Complex Numbers
Complex numbers are numbers of the form , where .
Addition/Subtraction: Combine real parts and imaginary parts separately.
Multiplication: Use distributive property and .
Example:
Example:
Solving an Equation by Factoring
Factoring can be used to solve equations by setting each factor equal to zero.
Example:
Solving Inequalities
Inequalities involve expressions related by <, ≤, >, or ≥.
Linear Inequality: Solve as you would an equation, but reverse the inequality sign when multiplying or dividing by a negative number.
Example:
Quadratic Inequality: Find zeros, test intervals, and determine where the inequality holds.
Graphs and Equations of Lines
Finding the Equation of a Line (Point-Slope Form)
The point-slope form is useful for writing the equation of a line when given a point and the slope.
Formula:
Example: Through (2, 3) with slope 4:
Finding the Equation of Parallel and Perpendicular Lines
Parallel lines have the same slope; perpendicular lines have slopes that are negative reciprocals.
Parallel: If a line has slope , any parallel line also has slope $m$.
Perpendicular: If a line has slope , a perpendicular line has slope (provided ).
Example: Line through (1, 2) parallel to :
Example: Line through (1, 2) perpendicular to :