Categories: All - functions - interest - polynomial - behavior

by Denice Ceniceros 5 years ago

238

mat151

The text covers various mathematical concepts and functions, focusing primarily on polynomial functions and their characteristics. It discusses the turning points of polynomial functions, where the function transitions between increasing and decreasing.

mat151

Denice Ceniceros Algebra

3.5

Transformation of a graph

  1. Great auntie- tries to stay near you, go the other direction (parenthesis)
  2. Example: (x-4) Go to the right 4, opposite of what you are told
  3. Elevator man- wants to get a tip so follows the same direction as in the equation
  4. Example: x+5 Go up 5 like the equation says to


3.3

More with imaginary numbers


Note: i= Sqrt -1 , i^2=-1


If a>0 , then sqrt -a = i sqrt a


  1. Simplify

Example: sqrt -16 Example: sqrt -3 X sqrt -3 | isqrt-3 X -isqrt3

=i sqrt 16 sqrt 9 | i^2sqr3 Xisqrt3

=4i =3WRONG | -1 (3) = -3 RIGHT

Example: 2 +_sqrt-24 Example: sqrt -2 X sqrt -8

2+i sqrt 24 /2 =i sqrt 2 X sqrt 8

2+isqrt 24 /2 i^2 sqrt 16

2+i sqrt 4 sqrt -1 (4)

=-4

i = sqrt -1 i^2=-1

Example: i+i=2i Example: 5i-3i=2i


Example: 5i X 3i= 15i^2 = 15(-1) =-15


Example: 5(-4i)= 20i Example: -6(2i-1)=12i+6


Example: 3i/21= 3/2 Example: (2i+1) (2i-1)= 4i^2-2i+2i-1

=4i^2 -1=4(-1)-1= -5

Complex Conjugates

  1. (2-3i)^2 2. -1(5-2i)^2

Check Notebook

Complex Conjugates

3 . 4+i/5-i X 5+i/5+i = 20+5i+4i+i^2/ 25-i^2

= 20+9i-1/25+1 = 19+9i/26


Complex Numbers and Exponents

i= Sqrt -1 , i^2=-1 , i^3 = i^2 X i =-1 X i =-i

i^4 =1 , i^5=i^4 X i =i , i^6= i^4 X i^2= -1

i^12= (i^4)^3= 1^3=1 i^50=(i^5)^10= i^10

=(i^2)^25=(-1)^25 = -1


  1. i^10 2. i^30 3.i^57 3.


3.2

Quadratic Formula

x= -b+- sqrt b^2-4 ac/2a

Graphically- X intercepts

(2 of these)

(1 of these)


Analysis

the Discriminant b^2-4ac

b^2-4ac > 0 2 real solutions

b^2-4ac=0 1 real solution

b^2-4ac <0 2 imaginary solutions


As long as the equation is of the form ax^2+bx+c=0 , I can use the quadratic formula.


Other ways to solve

  1. Complete the square when in standard form. (changes to vertex form)

Example 1: x^2 -8x +9 =0 1. Move the constant to the other side

x^2 -8x=-9 2. (b/2)^2 (8/2)^2=16

(x^2-8x +16)-16 =-9 3. Add and Subtract (b/2)^2

(x-4)(x+4)=-9+16

Sqrt (x-4)^2 = Sqrt 7 4. Put in vertex form

x-4 = +_ sqrt 7 5. Take square root


Example 2: x^2 - 8x=7 IN NOTEBOOK


Example 3: 3x^2 -6x +z=0

When a=/ 1 ...

3x^2 - 6x= -2

3( x^2 -2x ) =-2

3( x^2 -2x +1 -1)=-2

3(x^2-2x+1)+3(-1) =2

3(x-1)^2 = -2+3

3(x-1)^2 =1

(x-1)^2 =1/3

x-1=+_ Sqrt 1/3

x= 1+_ Sqrt 1/3


Factoring when factorable

Example: 2x^2 +2x-11=1

2x=^2+2x-12=0

2(x^2+x-6)=0

2(x-2)(x+3)=0 Divide by 2

(x-2)(x+3)=0

x-2=0 x+3=0

x=3 x=-3

3.1

  1. Degree is 2
  2. F(x)=ax2+bx+cax^2+bx+c (Standard Form)
  3. Graph- shape is parabolic (parabola)

If a>0, then upwards parabola

If a<0, then upside down parabola


Ex: Desmos

D:(-infinity, infinity)

{x|-infin. <x<infin.} - all real #'s

R: [0,inin.)

Increasing: (-infin.,0) Decreasing: (0,infin.)


4 . Verex Form f(x)=a(x+h)2+kf(x)=a(x+h)^2+k

(h,k) vertex


Ex: Find the equation given the vertex and a point on the curve.

V= (0,3) (2,1)

Need to find a and the vertex

1=a(2-0)^2+3

2=a(20)2-2=a(2-0)^2 Answer: f(x)=-1/2(x-0)^2+3

2=a(4)-2=a(4) f(x)= -1/2 x^2+3

1/4=a-1/4 =a

Find the equation given

V=(-2,4) and (3,6) Answer: F(x)= 2/25(x+2)^2

6=a(3+2)^2+4

2=a(5)^2

2/25=a


Find the function form given standard form


Ex: f(x)=2x^2-4x+1


Ex: b=4 a=2 x= --4/2(2)=1

f(1)= 2(1)^2-4(1)+1= -1 V=(1,-1)

Inequalities

  1. One variable x>3x>_-3

x+3x-2<4 --> 4x-2<4

4x<6 --> x<6/4=3/2 I.N = (-3,infinity)


2 . Two variables

Graph to find the solution set

y<3x+2 Test Point (-2,3) --> 3<3(-2)+2__ FALSE


3 . 2x+3y>_ -4

  1. Test point--(0,0) Answer on Desmos


4 . Absolute Value

|2x|=3

2x=3 or 2x=-3


5 . -2 |5x+10|=-4

-2/-2|5x+10| =-4/-2

|5x+10|<_ 2

5x+10=2 or 5x+10=-2

x<_ -8/5 x>_ -12/5

2.1

2.1 Linear Functions

Types of lines


Graphing

y=-2x+3


Parallel Lines-

Perpendicular-


Find the equation Given...

  1. 2 points
  2. (2,5) (1,0)

m= 0-5/1-2= -5/-1 =5

y-0= 5(x-1)

y=5x-5

2 . A point and the slope

Ex: (3,8) m=4/3

y-8= 4/3 (x-3)

y= 4/3x +4


3 . Line parallel to given line

y-0= -1/2 (x-0)

y=-1/2x


4 . Line perpendicular

m= 3/4 m2= -4/3 through (0,-3)

y--3= -4/3 (x-0)

y+3= -4/3x

y=-4/3 x-3

Chapter 2

4.4

Real zeros of higher degree polynomials


Example: f(x)=x3612+839x+4221f(x)=x^3-61^2+839x+4221 reps a

Small country's bird population , x days after May 31st.

Find the date(s) when the population was 5000. Find X when when f(x)= 5000 See Notes


Factoring to find zeros f(x)=ax^2+bx+c

F(x)= x^2-3x+2

0=(x-1)(x-2)

x-1=0 x-2=0

x=1 x=2


Zeros with Multiplicity (factored form) Graph


Example: f(x)=(x+2)^3 Example: F(x)= (x-4)^3(x+1)

=(x+2)(x+2) x=2 =4 Multiplicity

x=-1

Complete Factored Form

a) f(x)= 13x^2 -13x-26 b) f(x)=7x^3-2|x^2-7x+2|

GCF = 13 13(x^2-x-2) GCF= 7 (USe grouping method)

=13(x-2)(x+1) 7(x^3-3x^2)-(x-3)

0=13(x-2)(x+1) x=2 x=-1 7 [(x^3-3x^2)-(x-3)]

7[x^2(x-3)-(x-3)]

7(x-3)(x^2-1)

7(x-3)(x-1)(x+1) X=3,1,-1

C) F(x)=2x^3-4x^2-10x+12 (Use Graph)


Factoring Continued

a) f(x)= 2x^3-2x^2-34x-30 with given zero See Notes

If remainder = 0 ... TRUE FACTOR


Rational Zeros (Not all whole # zeros)

Let f(x)=

4.2

Polynomial Functions and Models


  1. Turning Point - Point when it goes from increasing to decreasing/decreasing to increasing _Cubic Function_
  2. End Behavior - f(x)--> - infin, x --> - infin


Example: See note book


Intercepts (x and y intercepts)

Example: See notebook x- intercepts (y=0)

zeros

Example: see notebook and desmos


3 . Piece wise Functions

F(x)= {x x>2 Slope=1

{2 x<_2 y-int=0

^ See notebook

{2x x>0

{x+2 x<0


Project - Compound Interest

FV=PV(1+i)^n

F+P(1+r)^t

#1 and 2# YOU TRY IT

F(x)+ax^2+bx+c F(1+r)^2+b(1+r)+c

4.1 Review

  1. Transformations of graphs
  2. Translations/ Reflections
  3. Minimum
  4. Maximum
  5. End behavior
  6. Increasing/ Decreasing Intervals
  7. Domain/ Range
  8. Even/ odd functions

4.1

Non Linear Functions

Symbolic Form for a polynomial

Example: y=mx+b OR f(x)=mx+b

F(x)= ax^m+bx^m-1+cx^m-2+. . . .

Graphs

Min and Max , Absolute Min , Absolute Max , Local Min , Local Max


Example: 2x3+3x2+x12x^3+3x^2+x-1 See Desmos

F(x)--> -infinity as x-->- infinity

F(x)--> infinity as x--> infinity


Example: 2x3+5x2+x22x^3+5x^2+x-2 See Desmos

Minimum - (-1.404,-3.557) Maximum - (0.5,0)

Increasing: ( Decreasing:

Domain: Range:

1.4 Types of functions

Types of Functions

Linear

Symbolic Form- y=mx+b (Slope intercept form)Highest exponent degree is 1.Ex: y=3x+1(Vertical Line)x=2 (a line that is NOT function)(Horizontal Line) y=2 (is a function)


Quadratic y=ax^2+bx+cHighest Degree is 2.Ex: y=x2+2x+1y=x^2+2x+11a. f(x)=3x2+4x+2f(x)=3x^2+4x+21b. a>02a. a<02b. f(x)=x2+2x+1f(x)=-x^2+2x+1


Cubicf(x)=ax3+bx2+cx+df(x)=ax^3+bx^2+cx+d(a,b,c,d are constants)Highest exponent is 3.y=x3y=x^3 f(x)=6x3f(x)=6x^3a>0 -- Regular parabolaa<0 -- Upside down parabola


Quarticf(x)=ax4+bxcx2+dx+ef(x)=ax^4+bx^cx^2+dx+eDegree is 4.Ex:a>0 --a<0 --


Rationalf(x)=a/xh+kf(x)=a/x-h +kx-h DOES NOT EQUAL 0Ex:f(x)=(3/x+2)f(x)=(3/x+2)


Exponentialf(x)=(a)(bx)f(x)=(a)(b^x)(a,b are constants)Ex: a=1a=1 , f(x)=33f(x)=3^3Ex: f(x)=exf(x)= e^x( e is a constant)Ex: a=1/2a= 1/2 f(x)=1/2(2x)f(x)=1/2(2^x)Logarithmic Absolute Value Functionsf(x)=xh+kf(x)=|x-h|+kEx: f(x)=xf(x)=|x|Average rate of change- (Slope)y2y1/x2x1=f(x2)f(x1)/x2x1y2-y1/x2-x1=f(x2)-f(x1)/x2-x1Ex: f(x)=2x2f(x)=2x^2 (1,3) find average{interval} rate of changef(2)f(3)/23f(-2)-f(-3)/-2--3(-3,-2)Difference Quotientf(xh)f(x)/(x+h)xf(x-h)-f(x)/(x+h)-x = f(x+h)f(x)/hf(x+h)-f(x)/h Ex: f(t)=16t2+16t+32f(t)=-16t^2+16t+32(0,2) 16t2+16t+32-16t^2+16t+32f(0)=32f(2)= 0f(2)f(0)/20=032/20=32/2=16f(2)-f(0)/2-0 = 0-32/2-0=-32/2=-16

1.3 Functions

1.3 Functions and their representations

Definitions:

  1. Variable- a symbol /letter that represents an unknown number
  2. Dependent Variable- "y" output
  3. Independent Variable- "x" input
  4. Equation- two equal algebraic expressions
  5. Relation- comparing at least two things (usually x and y)
  6. Function- relation where each input has only one output


  1. y=x2y=x^2
  2. () Not equal
  3. [] Equal to

Chapter 1