Chapter 3 • Complex Numbers • Quadratic Functions and Equations • Inequalities • Rational Equations • Radical Equations • Absolute Value Equations
Willa Cather –U.S. novelist • “Art, it seems to me, should simplify. That indeed, is very nearly the whole of the higher artistic process; finding what conventions of form and what detail one can do without and yet preserve the spirit of the whole – so that all one has suppressed and cut away is there to the reader’s consciousness as much as if it were in type on the page.
Mathematics 116 • Complex Numbers
Set of Complex Numbers • R = real numbers • I = imaginary numbers • C = Complex numbers
Elbert Hubbard • “Positive anything is better than negative nothing.”
Standard Form of Complex number • a + bi • Where a and b are real numbers • 0 + bi = bi is a pure imaginary number
Equality of Complex numbers • a+bi = c + di • iff • a = c and b = d
Add and subtract complex #s • Add or subtract the real and imaginary parts of the numbers separately.
Orison Swett Marden • “All who have accomplished great things have had a great aim, have fixed their gaze on a goal which was high, one which sometimes seemed impossible.”
Multiply Complex #s • Multiply as if two polynomials and combine like terms as in the FOIL • Note i squared = -1
Complex Conjugates • a – bi is the conjugate of a + bi • The product is a rational number
Divide Complex #s • Multiply numerator and denominator by complex conjugate of denominator. • Write answer in standard form
Harry Truman – American President • “A pessimist is one who makes difficulties of his opportunities and an optimist is one who makes opportunities of his difficulties.”
Calculator and Complex #s • Use Mode – Complex • Use i second function of decimal point • Use [Math][Frac] and place in standard form a + bi • Can add, subtract, multiply, and divide complex numbers with calculator.
Mathematics 116 • Solving Quadratic Equations • Algebraically • This section contains much information
Def: Quadratic Function • General Form • a,b,c,are real numbers and a not equal 0
Objective – Solve quadratic equations • Two distinct solutions • One Solution – double root • Two complex solutions • Solve for exact and decimal approximations
Solving Quadratic Equation #1 • Factoring • Use zero Factor Theorem • Set = to 0 and factor • Set each factor equal to zero • Solve • Check
Solving Quadratic Equation #2 • Graphing • Solve for y • Graph and look for x intercepts • Can not give exact answers • Can not do complex roots.
Solving Quadratic Equations #3Square Root Property • For any real number c
Procedure • 1. Use LCD and remove fractions • 2. Isolate the squared term • 3. Use the square root property • 4. Determine two roots • 5. Simplify if needed
Dorothy Broude • “Act as if it were impossible to fail.”
Completing the square informal • Make one side of the equation a perfect square and the other side a constant. • Then solve by methods previously used.
Procedure: Completing the Square • 1. If necessary, divide so leading coefficient of squared variable is 1. • 2. Write equation in form • 3. Complete the square by adding the square of half of the linear coefficient to both sides. • 4. Use square root property • 5. Simplify
Objective: • Solve quadratic equations using the technique of completing the square.
Mary Kay Ash • “Aerodynamically, the bumble bee shouldn’t be able to fly, but the bumble bee doesn’t know it so it goes flying anyway.”
College AlgebraVery Important Concept!!! • The • Quadratic • Formula
Objective of “A” students • Derive • the • Quadratic Formula.
Quadratic Formula • For all a,b, and c that are real numbers and a is not equal to zero
Pearl S. Buck • “All things are possible until they are proved impossible and even the impossible may only be so, as of now.”
Methods for solving quadratic equations. • 1. Factoring • 2. Square Root Principle • 3. Completing the Square • 4. Quadratic Formula
Discriminant • Negative – complex conjugates • Zero – one rational solution (double root) • Positive • Perfect square – 2 rational solutions • Not perfect square – 2 irrational solutions
Joseph De Maistre (1753-1821 – French Philosopher • “It is one of man’s curious idiosyncrasies to create difficulties for the pleasure of resolving them.”
CalculatorPrograms • ALGEBRAQUADRATIC • QUADB • ALG2 • QUADRATIC
Ron Jaworski • “Positive thinking is the key to success in business, education, pro football, anything that you can mention. I go out there thinking that I’m going to complete every pass.”