<< Chapter < Page Chapter >> Page >

Given the toolkit function f ( x ) = x 2 , graph g ( x ) = f ( x ) and h ( x ) = f ( x ) . Take note of any surprising behavior for these functions.

Graph of x^2 and its reflections.

Notice: g ( x ) = f ( x ) looks the same as f ( x ) .

Got questions? Get instant answers now!

Determining even and odd functions

Some functions exhibit symmetry so that reflections result in the original graph. For example, horizontally reflecting the toolkit functions f ( x ) = x 2 or f ( x ) = | x | will result in the original graph. We say that these types of graphs are symmetric about the y -axis. A function whose graph is symmetric about the y -axis is called an even function.

If the graphs of f ( x ) = x 3 or f ( x ) = 1 x were reflected over both axes, the result would be the original graph, as shown in [link] .

Graph of x^3 and its reflections.
(a) The cubic toolkit function (b) Horizontal reflection of the cubic toolkit function (c) Horizontal and vertical reflections reproduce the original cubic function.

We say that these graphs are symmetric about the origin. A function with a graph that is symmetric about the origin is called an odd function .

Note: A function can be neither even nor odd if it does not exhibit either symmetry. For example, f ( x ) = 2 x is neither even nor odd. Also, the only function that is both even and odd is the constant function f ( x ) = 0.

Even and odd functions

A function is called an even function    if for every input x

f ( x ) = f ( x )

The graph of an even function is symmetric about the y - axis.

A function is called an odd function    if for every input x

f ( x ) = f ( x )

The graph of an odd function is symmetric about the origin.

Given the formula for a function, determine if the function is even, odd, or neither.

  1. Determine whether the function satisfies f ( x ) = f ( x ) . If it does, it is even.
  2. Determine whether the function satisfies f ( x ) = f ( x ) . If it does, it is odd.
  3. If the function does not satisfy either rule, it is neither even nor odd.

Determining whether a function is even, odd, or neither

Is the function f ( x ) = x 3 + 2 x even, odd, or neither?

Without looking at a graph, we can determine whether the function is even or odd by finding formulas for the reflections and determining if they return us to the original function. Let’s begin with the rule for even functions.

f ( x ) = ( x ) 3 + 2 ( x ) = x 3 2 x

This does not return us to the original function, so this function is not even. We can now test the rule for odd functions.

f ( x ) = ( x 3 2 x ) = x 3 + 2 x

Because f ( x ) = f ( x ) , this is an odd function.

Got questions? Get instant answers now!
Got questions? Get instant answers now!

Is the function f ( s ) = s 4 + 3 s 2 + 7 even, odd, or neither?

even

Got questions? Get instant answers now!

Graphing functions using stretches and compressions

Adding a constant to the inputs or outputs of a function changed the position of a graph with respect to the axes, but it did not affect the shape of a graph. We now explore the effects of multiplying the inputs or outputs by some quantity.

We can transform the inside (input values) of a function or we can transform the outside (output values) of a function. Each change has a specific effect that can be seen graphically.

Vertical stretches and compressions

When we multiply a function by a positive constant, we get a function whose graph is stretched or compressed vertically in relation to the graph of the original function. If the constant is greater than 1, we get a vertical stretch ; if the constant is between 0 and 1, we get a vertical compression . [link] shows a function multiplied by constant factors 2 and 0.5 and the resulting vertical stretch and compression.

Questions & Answers

what is cell
Oppicial Reply
To know how bones are functions
DAUDA Reply
diagram of the heart
Victoria Reply
what are the layers of the muscles
Tongdock Reply
What is Amebae
Najibu Reply
the collection of fluids in the throat is cause by what
Emmanuel Reply
what is difference between meiosis and mitosis
Aishetu Reply
what is difference between mitosis and meiosis
Aishetu
What is Anatomy
Najibu Reply
What the difference between the Anatomy and physiology
Najibu
What is the meaning of chromoprotein
Aisha Reply
what is cartilage
Abdulkadir Reply
tough , white fibrous tissue
Henry
distinguish between anatomy and physiology
Amina Reply
Anatomy is the study of internal structure of an organism while physiology is the study of the function/relationship of the body organs working together as a system in an organism.
adeyeye
distinguish between anatomy and physiology
Erny Reply
regional anatomy is the study of the body regionally
Ismail Reply
what is the meaning of regional anatomy
Aminat Reply
epithelial tissue: it covers the Hollow organs and body cavities
Esomchi Reply
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Algebra and trigonometry. OpenStax CNX. Nov 14, 2016 Download for free at https://legacy.cnx.org/content/col11758/1.6
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Algebra and trigonometry' conversation and receive update notifications?

Ask