Function
mathematical relation; maps a set of input values to a set of output values (each input has 1 output)
Domain (independent variable)
Set of input values
Range (dependent variable)
Set of output values
Domain restriction
x-values restricted from one value to another (used in graphing) (ex. -4 _< x _< 4)
Positive ROC (increasing graph behavior)
As one quantity inc., the other inc.
Negative ROC (decreasing graph behavior
As
Concave up
ROC is increasing
Concave down
ROC is decreasing
Open intervals
Use “( )” when doing notation of x-values
Average ROC
The slope of any two points
Instantaneous ROC
ROC of a given point (in pre calc: finding ROCs of small intervals near the given point)
Linear function
Average ROC over any length input value interval is constant (constant ROC) (slope of line)
Consecutive equal length input value intervals (CELIVI)
x-values increasing by the same length amount (ex. x-values are consistently increasing by length 2)
Quadratic functions
Quadratic functions follow a linear pattern for the average ROC.
Polynomial function
Any function representation equal to the formula: p(x) = a_nx^n + a_n-1x^n-1 + a_n-2x^n-2 + … + a_2x^2 + a_1x + a_0 . n =positive integer, a_i = real number for each “i” from 1 to n, a_n = nonzero
Extrema
The minimums and the maximums of a function
Relative (Local) extrema
Where it switches from dec. to inc. or at an endpoint if poly. has a restricted domain)
Absolute (global) extrema
From all of the local extremas, the greatest (max.) or least (mini.) is the absolute extrema.
Point of inflection
When a function changes from concave up to concave down (or vise versa). ROC changes from inc. to dec. (vise versa)
Sum/ Diff. Of 2 cubes
a^3-b^3 =(a-b)(a^2+ab+b^2)
a^3+b^3 =(a+b)(a^2-ab+b^2)
Imaginary number ‘i’
Defined as i=(square root) -1 or i^2=-1
Complex number
Any number written in a+bi form; a and b are real numbers and i is imaginary unit.
Power pattern of i
i^1=i, i^2=-1, i^3=-i, i^4=1
Complex conjugates
Two complex numbers in form a+bi and a-bi are called complex conjugates; products of these conjugates are always a real number.
Methods to solve quadratic equations w/ complex zeros
Start w/ factoring then go to…
Case 1: when there is no x-term, solve w square roots
Case 2: coefficient of x^2 term is 1 and coefficient of x term is even number; completing the square
Case 3: equation not factorable, completing square leads to fractions; quadratic formula (x=-b +- (square root) b^2-4ac/2a)
Zero or root
if p(a)=0; if a is real, (x-a) is linear factor of p
Multiplicity of zeros
Linear factor (x-a) is repeated n times in factored form of polynomial function; corresponding zero has that n amount in multiplicity.
Multiplicity graph behaviors
n=1: crosses x-axis
n= odd & greater than or equal to 3: point of inflection (switching roc from incr. to decrease. and vise versa)
n= even: tangent to x-axis
Conjugate pairs
All imaginary roots come in pairs: a+bi and a-bi
Fundamental Theorem of Algebra
A polynomial of degree n has exactly n complex zeros (counting multiplicities)
f(x) >0
graph of f(x) is above x-axis
f(x) <0
Graph of f(x) is below x-axis
Even functions
Symmetric over y-axis; f(-x)=f(x); in function, even exponents
Odd functions
Symmetric about the origin; g(-x)=-g(x); odd exponents
Finding degree of polynomial in table
Look for when the successive differences become constant.
End behavior
Describes how a function behaves as it moves indefinitely to the left and right; what happens to y-values as x incr. and decr. w/o bound
Finding end behavior in polynomials
Start w right side…
If leading coef. is positive, right goes positive
If leading coef. is negative, right goes negative
Left:
If degree is even; goes same direction as right
If degree is odd; goes different than right
Graphing lines w/ domain restrictions
Graph equation like normal
Only keep portion of function indicated by domain restriction
X<# or x<_#
Graph to left of x-value
X># or x>_#
Graph to the right of the x-value
#<x<#
Segment in between two x-values
< or >
Open circle (not included)
Closed circle (included)
Piecewise function
Consists of different function rules for diff parts of the domain
Special types of Piecewise functions
Absolute value
Step (greatest integer)
Absolute Value Functions
y= a|x-h| +k, vertex= (h,k)
Steps to graphing:
Vertex point
a=slope, draw to the right of vertex point
Mirror line on left side
Step (greatest integer) function
Written as f(x)=[|x|] (type of step function)
[|x|]= greatest integer less than or equal to x
Limits of Piecewise functions
lim x→a : two sided limit
lim x→a+ : right-handed limit
lim x→a- : left handed limit
For a two-sided limit to exist…
Both one side limits must exist
Meet at same value