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Algebra Formulas
(Midterm) Formulas having to do with functions mostly
67
Mathematics
Undergraduate 1
02/15/2010

Additional Mathematics Flashcards

 


 

Cards

Term
Looking at a graph, how can you tell if it is a function?
Definition

Vertical Line Test:

 

Vertical line should not intersect graph in more than one place. If it does, then it is not a function.

Term

The output variable and the input variable:

 

Which one is dependent, and which is independent?

Definition

The output variable is dependent

(it depends upon the input)

 

The input variable is independent

(may have its value freely chosen regardless of any other variable values)

 

 

The output is a function of (depends upon) the input

Term

The DOMAIN (or INPUT) is on the _____ axis.

 

The RANGE (or OUTPUT) is on the _____ axis.

Definition

The domain is x (x-axis)

 

The range is f(x) or y (y-axis)

Term
Pythagorean Theorem for a Right Triangle
Definition

L2 + H2 = D2

 

L = Length

H = Height

D = Diagonal

Term
Area of a Circle
Definition
(pi) r2
Term
Area of a Triangle
Definition

(B x H)

---------

2

Term

Vertical Shift of Function (up/down):

 

Horizontal Shift of Function (left/right):

Definition

Vertical Shift of Function (up/down):

Add or subtract from the function

EG: f(x) → f(x) + 5 will move up 5 units

 

Horizontal Shift of Function (left/right):

Add or subtract the reverse from x

EG: f(x) → f(x-5) will move right 5 units

Term

Reflect Function Across x-axis:

 

Reflect Function Across y-axis:

Definition

Reflect Function Across x-axis:

Multiply function by -1

EG: f(x) → -f(x) will mirror across x-axis

 

Reflect Function Across y-axis:

Multiply x by -1

EG: f(x) → f(-x) will mirror across y-axis

Term

Vertically Stretch Graph of a Function:

 

Vertically Shrink Graph of a Function:

Definition

Vertically Stretch Graph of a Function:

Multiply function by a number greater than 1

EG: f(x) → 3f(x) will vertically stretch the graph

 

Vertically Shrink Graph of a Function:

Multiply function by a number between 0 and 1

EG: f(x) → 0.5f(x) will vertically shrink the graph

Term

Horizontally Stretch Graph of a Function:

 

Horizontally Shrink Graph of a Function:

Definition

Horizontally Stretch Graph of a Function:

Multiply x by a number between 0 and 1

EG: f(x) → f(0.5x) will horizontally stretch the graph

 

Horizontally Shrink Graph of a Function:

Multiply x by a number greater than 1

EG: f(x) → f(3x) will horizontally shrink the graph

Term
Odd and Even Functions
Definition

f(x) = f(-x) is EVEN

(symmetry about the y-axis)

 

f(x) = -f(x) not possible except for 0

(symmetry about the x-axis)

 

-f(x) = f(-x) and f(-x) = -f(x) are ODD

(symmetry about the origin)

Term
How to find the inverse of a function:
Definition

1. Replace f(x) with y

 

2. Solve for x in terms of y (x on one side, alone)

 

3. Interchange x and y, then replace y with f-1(x)

Term

Is this a function?

 

X: 3, 2, 4, 6, 8, 12

Y: 3, 3, 7, 12, 4, 8

Definition

Yes - passes Vertical Line Test

 

All Domain values are unique

Term

Is this a function?

 

X: 3, 2, 4, 3, 8, 12

Y: 3, 3, 7, 12, 4, 8

Definition

No - does not pass Vertical Line Test

 

Domain contains duplicates (3 corresponds to two values in the range- 3 and 12)

Term
Slope of a Linear Function in terms of Rise and Run
Definition

          Rise

Slope = ----------

          Run

Term
Standard Form of a Linear Function
Definition

y or f(x) = mx + b

 

m is the slope

 

b is the y-intercept

Term
How to calculate slope from coordinates of 2 points on the line:
Definition

For (x1, y1) (x2, y2)

 

     y2 - y1

M = -----------

     x2 - x1

Term
Point-Slope Form
Definition

y or f(x) = m(x-x1) + y1

 

(x-x1) ends up being x

 

y1 ends up being b or y-intercept

Term
How to find the root of a linear function:
Definition

Calculate y = mx + b as

0 = mx + b

Term

Parallel lines have slopes that are ______

 

Perpendicular lines have slopes that are ______

Definition

Parallel lines have slopes that are EQUAL

EG: m1 = m2

 

Perpendicular lines have slopes that are

NEGATIVELY RECIPROCAL

EG: m1 = -1/m2   or   m2 = -1/m1

Term
How to find the point of intersection of 2 lines:
Definition

For two lines     y1=m1x1+b1    and    y2=m2x2+b2

 

                               b2-b1

Point of intersection (x0) is ------------

                               m1-m2

 

 

(then can use this as x to find y)

Term

In regression analysis,

 

r is ________

 

and r2 is ________

Definition

r is the CORRELATION COEFFICIENT

(a number between -1 and 1 that measures how well the best fitting line fits the data points)

 

r2 is the COEFFICIENT OF DETERMINATION

(a number that determines if the best fitting line can be used as a data model. Closer to 1, the better the fit)

Term
Standard form of a Quadratic Function
Definition

y or f(x) = ax2+bx+c

 

(a≠0, if a=0 then it is a horizontal line)

Term
Standard Form vs. Vertex Form of a Quadratic Function
Definition

Standard Form

y or f(x) = ax2+bx+c

 

Vertex Form

y or f(x) = a(x-h)2+k

 

-h,k are the x,y of the vertex

Term

Move the vertex of

 

f(x) = 3x2+1 to (-3,2)

Definition

Replace old x with new x

3x2 → 3(x+3)2

remember, x moves the opposite way

 

Replace old y with new y

+1 → +2

 

3x2+1 → 3(x+3)2 +2

Term
Finding the Vertex of a Quadratic Function
Definition

    -b

x = ------

     2a

 

 

Plug this into the equation to find y

 

 

Term
Finding the roots of a Quadratic Function:
Definition

The root(s) are at

0 = ax2+bx+c

 

Use the Quadratic Formula:

 

    -b ± √b2 - 4ac

x= --------------------

    2a

Term

What is the Quadratic Formula?

 

What is it used for?

Definition

Quadratic Formula

 

    -b ± √b2 - 4ac

x= --------------------

    2a

 

Quadratic Formula is used to find the roots of a quadratic function

Term
What is the Discriminant and what can it tell you?
Definition

The Discriminant is the b2 - 4ac part of the Quadratic Function

 

If the Discriminant is positive, there are two roots

 

If the Discriminant is zero, there is one root, the graph is sitting on the x-axis

 

If the Discriminant is negative, the graph does not intersect the x-axis (there is no root)

Term

What kind of function is this:

 

f(x) = mx + b

Definition
Linear Function
Term

Linear Regression Analysis

 

What is the correlation coefficient and how is it represented?

Definition

correlation coefficient = r

 

Measures how well the best fitting line fits the data points. Ranges from -1 to 1.

Term

Linear Regression Analysis

 

What is the coefficient of determination and how is it represented?

Definition

Coefficient of Determination = r2 (the square of the correlation coefficient). Determines if the best fitting line can be used as a model (is it good enough?)

 

The closer r2 is to 1, the better the fit.

Term

What kind of function is this:

 

f(x) = ax2 + bx + c

Definition

Quadratic Function

 

(a ≠ 0)

 

The simplest form of a quadratic function is

f(x) = x2

 

a.k.a. a power function

Term

What kind of function is this:

 

ax4 + ax3 + ax2 + ax + a

Definition

Polynomial Function

 

(of degree 4 - quartic polynomial)

Term
Standard form of a Polynomial Function
Definition

ax4 + ax3 + ax2 + ax + a

 

(the exponent cannot be negative,

the exponent cannot be a fraction,

x cannot be in the denominator)

Term

If the first (largest) term in a polynomial function is

 

ax4 the function is ____________

 

ax3 the function is ____________

 

ax2 the function is ____________

 

ax the function is  ____________

 

ax0 ________________

Definition

If the first (largest) term in a polynomial function is

 

ax4 the function is quartic (parabola)

ax3 the function is cubic (snakelike)

ax2 the function is quadratic (parabola)

ax the function is linear (line)

ax0 is a horizontal line at y=a

Term

Polynomial Function

 

bx4 + ax3 + ax2 + ax + g

 

What is b?

What is 4?

What is g?

What is bx4?

 

 

Definition

b is the leading coefficient

4 is the degree/order

g is the constant term

bx4 is the leading term

Term
f(x) = axn
Definition

f(x) = axn

 

is a monomial function

is a power function

 

(n > 0

b ≠ 0)

Term

f(x) = axn

 

if n=0, graph is _________________

 

if n=1, graph is _________________

 

if n=2, graph is _________________

 

if n=3, graph is _________________

Definition

f(x) = axn

 

if n=0, graph is a horizontal line at y=a

 

if n=1, graph is linear with slope of a (odd function)

 

if n=2, graph is parabola, branches facing up when a is a is positive, down when a is negative (even function)

 

if n=3, graph is snakelike, increasing when a is positive, decreasing when a is negative (odd function)

Term

Even-exponent Power Functions

 

xn → n could equal _____

 

the shape is _______

 

graph gets ______ the _______ the exponent

 

When x>1 or x<-1, ______ are ________

 

When -1>x>1, _______ are ________

Definition

xn → n could equal 2, 4, etc.

 

the shape is a parabola

 

graph gets flatter (on the bottom) the higher the exponent

 

When x>1 or x<-1, branches are steeper

 

When -1>x>1, branches are flatter

Term

Odd-exponent Power Functions

 

xn → n could equal _____

 

the shape is _______

 

graph gets ______ the _______ the exponent

 

When x>1 or x<-1, ______ are ________

 

When -1>x>1, _______ are ________

Definition

xn → n could equal 1, 3, 5, etc.

 

the shape is snakelike

 

graph gets flatter (on the bottom) the higher the exponent

 

When x>1 or x<-1, traces are steeper

 

When -1>x>1, traces are flatter

Term

Intermediate Value Theorem

 

(polynomial functions)

Definition

If the result of f(a) and f(b) are opposite signs (+/-), then there must be at least one root between them

 

(as long as a≠b)

Term

Factor Theorem

 

(polynomial functions)

Definition

f(c) will equal zero ONLY IF (x-c) is a factor of the polynomial.

 

In other words, the factors (x-c) are the only places where the function will equal zero.

Term

i2 =

 

√-16 =

Definition

i2 = -1

 

√-16 = √16 i = 4i

Term

(x-c)3 has a _________ of _____

 

if x=4, the factor of the polynomial is ______

 

if x = -3, the factor of the polynomial is ______

Definition

(x-c)3 has a multiplicity of 3

 

if x=4, the factor of the polynomial is (x-4)

 

if x = -3, the factor of the polynomial is (x+3)

Term

(x-c)3 will _____ the x-axis at the x=c

 

(x-c)2 will _____ the x-axis at the x=c

Definition

(x-c)3 will cross the x-axis at the x=c

 

(x-c)2 will touch the x-axis at the x=c

Term
How do you represent a polynomial factor that does not cross or touch the x-axis anywhere?
Definition

The constant factor k

 

f(x) = k(x-c1)(x-c2)(x-c3)

 

Adding or subtracting from the constant factor k shifts the graph up or down the y-axis

Term

A polynomial of degree/order "n" can have a maximum of ___ roots

 

A polynomial of degree/order "n" can have a maximum of ___ turning points

Definition

A polynomial of degree/order "n" can have a maximum of n roots

 

A polynomial of degree/order "n" can have a maximum of n-1 turning points

Term

Finding the rational (not irrational) zeros of a polynomial function:

 

Rational Zeros Theorem

Definition

p (all rational factors of constant term)     

___                                                         

 

r (all rational factors of leading coefficient)

 

any of these that lead to f(x)=0 are the rational zeros

Term

A quadratic function can have ____ turning points

 

A cubic function can have ____ turning points

 

A quartic function can have ____ turning points

Definition

A quadratic function can have 1 turning point

 

A cubic function can have 2 turning points

 

A quartic function can have 3 turning points

Term

Polynomial Functions

 

When the absolute value of x is large, end/long-run behavior of the graph will tend to ______

Definition
When the absolute value of x is large, end/long-run behavior of the graph will tend to follow the leading term
Term

For every polynomial function where the degree is >0, there are complex numbers such that

f(x)=a(x-c1) (x-c2)... etc...

 

(as long as a≠0)

 

This is known as _____________

Definition

The Linear Factorization Theorem

 

 

For every polynomial function where the degree is >0, there are complex numbers such that

f(x)=a(x-c1) (x-c2)... etc...

 

(as long as a≠0)

Term

Every polynomial of a degree of ≥1 with complex coefficients has at least one zero in the complex number system.

 

This is called _______________

Definition

The Fundamental Theorem of Algebra

 

 

Every polynomial of a degree of ≥1 with complex coefficients has at least one zero in the complex number system.

Term

What kind of function is this:

 

        p(x)

f(x)= -----------

        q(x)

Definition
Rational Function
Term

What kind of function is this:

 

        ax3+bx2+cx+d

f(x)= -------------------------

        ax4+bx3+cx2+dx+e

Definition
Rational Function
Term
What is the domain of a rational function?
Definition

The domain of a rational function is the set of all real numbers that are NOT roots of the denominator

(the denominator≠0)

Term

(x-2)(x+6)2

----------------

(x-2)(x-6)

 

1. Root(s)/Zero(s):

2. Vertical Asymptote(s):

3. Hole(s):

4. Degree of numerator/denominator:

Definition

(x-2)(x+6)2

----------------

(x-2)(x-6)

 

1. Root(s)/Zero(s): -6

2. Vertical Asymptote(s): 6

3. Hole(s): 2

4. Degree of numerator/denominator: 3/2

Term

x3+10x2+12x-72

-----------------------

x2-8x+12

 

1. Y-intercept:

2. Horizontal Asymptote(s):

3. End behavior of graph:

4. Degree of numerator/denominator:

Definition

x3+10x2+12x-72

-----------------------

x2-8x+12

 

1. Y-intercept: x=0 is not a root of the denominator, so evaluate function at x=0. y=-6

2. Horizontal Asymptote(s): oblique asymptote, divide the equation to find it. x+18

3. End behavior of graph: x3/x2 which would be a line increasing as x increasing that crosses the graph at x=2 and x=6

4. Degree of numerator/denominator: 3/2

Term

Negative or positive? What degree?

 

[image]

Definition

Negative

 

Odd

Term

Negative or positive? What degree?

 

[image]

Definition

Positive

 

Odd

Term

Negative or positive? What degree?

 

[image]

Definition

Negative

 

Even

Term

Negative or positive? What degree?

 [image]

 

Definition

Positive

 

Even

Term

Asymptote of

 

an

-------

bn

Definition

Horizontal asymptote at

 

y=a/b

Term

Asymptote of

 

an

------

bN

Definition

Horizontal asymptote at

 

y=0

Term

Asymptote of

 

aN

------

bn

Definition

Oblique asymptote at

 

(divide the equation to find it)

Term

Asymptote of

 

aNN

---------

bn

Definition
No line asymptote
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